Multiple Functions of MYB Transcription Factors in Abiotic Stress Responses

Genome-wide identification and analysis of the NF-Y transcription factor family reveal its potential roles in tobacco (Nicotiana tabacum L.)

Nuclear Factor Y (NF-Y) represents a group of transcription factors commonly present in higher eukaryotes, typically consisting of three subunits: NF-YA, NF-YB, and NF-YC. They play crucial roles in the embryonic development, photosynthesis, flowering, abiotic stress responses, and other essential processes in plants. To better understand the genome-wide NF-Y domain-containing proteins, the protein physicochemical properties, chromosomal localization, synteny, phylogenetic relationships, genomic structure, promoter cis-elements, and protein interaction network of NtNF-Ys in tobacco (Nicotiana tabacum L.) were systematically analyzed. In this study, we identified 58 NtNF-Ys in tobacco, respectively, and divided into three subfamilies corresponding to their phylogenetic relationships. Their tissue specificity and expression pattern analyses for leaf development, drought and saline-alkali stress, and ABA response were carried out using RNA-seq or qRT-PCR. These findings illuminate the role of NtNF-Ys in regulating plant leaf development, drought and saline-alkali stress tolerance, and ABA response. This study offers new insights to enhance our understanding of the roles of NtNF-Ys and identify potential genes involved in leaf development, as well as drought and saline-alkali stress tolerance of plants.

Tea polyphenol mediated CsMYB77 regulation of CsPOD44 to promote tea plant (Camellia sinensis) root drought resistance

Drought stress significantly alters the metabolic homeostasis of tea plants; however, few studies have examined the role of specific metabolites, particularly tea polyphenols, in drought resistance. This study reveals that the tea polyphenol content in drought-tolerant tea cultivars tends to increase under drought conditions. Notably, in environments characterized by staged and repeated drought, changes in tea polyphenol are significantly positively correlated with drought resistance. To investigate this further, we irrigated the roots with exogenous tea polyphenols before subjecting the plants to drought. Our findings indicated that the absorptive roots of the experimental group exhibited enhanced development, improved cellular integrity, and a significant increase in peroxidase activity. A comprehensive analysis of the transcriptome and metabolome revealed that tea polyphenols are closely associated with the phenylpropanoid metabolism pathway. Notably, CsMYB77 and CsPOD44 genes were identified as highly correlated with this pathway. Overexpression experiments in Arabidopsis thaliana demonstrated that CsMYB77 promotes the expression of phenylpropanoid pathway genes, thereby enhancing drought resistance. Conversely, antisense oligonucleotide silencing of CsMYB77 decreased drought resistance in tea plants. Additional experiments, including yeast one-hybrid assays, luciferase complementation imaging, dual-luciferase assays, and electrophoretic mobility shift assays, confirmed that CsMYB77 positively regulates the expression of CsPOD44. In summary, our findings indicate that the differences in drought tolerance among tea cultivars are closely linked to phenylpropanoid metabolism. Specifically, tea polyphenols may mediate the regulatory network involving CsMYB77 and CsPOD44, thereby enhancing stress resistance by promoting root development. This study offers new insights into the breeding of drought-resistant tea cultivars.

Bioinformatics analysis and development of functional markers for TaMYB4-1A in wheat

MYB transcription factors play crucial roles in various stages of plant growth and development. Bioinformatics analysis revealed that wheat TaMYB4-1A contains two conserved MYB domain. The coding region of TaMYB4-1A is 792 bp, encoding 263 amino acids. TaMYB4-1A is a hydrophilic protein, and its encoded protein is localized in the cell nucleus. Evolutionary tree analysis indicates that the TaMYB4 protein shares the closest relationship with Aegilops, barley, and rye. Tissue-specific expression analysis revealed that TaMYB4-1A is expressed in wheat roots, stems, leaves, and seeds 14 days post-flowering, with the highest expression in the seeds. Promoter cis-acting element analysis showed that the promoter region of TaMYB4-1A contains various cis-acting elements, including meristem regulatory elements, drought-induced elements, and hormone response elements. qRT-PCR analysis showed that the expression of TaMYB4-1A is suppressed under high salinity and PEG treatment, suggesting that TaMYB4-1A may play a critical regulatory role in response to salt and drought stress. There are two haplotypes of TaMYB4-1A, namely Hap-1A-I and Hap-1A-II. The average plant height of varieties with haplotype Hap-1A-I is significantly higher than that of varieties with haplotype Hap-1A-II. This research provides a basis for future in-depth investigation of the biological function of the TaMYB4-1A gene and offers promising candidate genes for molecular marker-assisted wheat breeding.

The drought-responsive wheat AP2/ERF transcription factor TaRAP2-13L and its interacting protein TaWRKY10 enhance drought tolerance in transgenic Arabidopsis and wheat (Triticum aestivum L.)

AP2/ERF transcription factors (TFs) are one of the largest TF families involved in plant growth, development, and stress responses. Drought, a major abiotic stress, severely impacts wheat yield and quality. In this study, we identified a wheat AP2/ERF gene, TaRAP2-13L, which was significantly upregulated in response to drought stress. Subcellular localization and transcriptional activity assays indicated that TaRAP2-13L localizes in the nucleus but lacks transcriptional activity. Overexpression of TaRAP2-13L in Arabidopsis enhanced drought tolerance, while silencing TaRAP2-13L in wheat reduced drought tolerance by modulating the ABA signaling pathway and reactive oxygen species homeostasis. Through yeast two-hybrid screening, TaWRKY10 was identified as an interacting protein of TaRAP2-13L, and their interaction was further confirmed by bimolecular fluorescence complementation, luciferase complementation imaging assays, and GST pull-down assays. Functional analysis revealed that TaWRKY10 exhibited a similar role to TaRAP2-13L in drought response. Transcriptional regulation analysis showed that co-expression of TaRAP2-13L and TaWRKY10 complex significantly enhanced transcriptional activity, particularly under drought conditions induced by PEG6000. Moreover, dual-luciferase assays demonstrated that TaRAP2-13L and TaWRKY10 can activate the expression of TaSOD3-2A, TaSOD3-2D, TaGPX1-D, and TaNCED2-5B, with co-expression of both TFs enhancing this activation. Further assays revealed that TaRAP2-13L binds to the DRE motif, TaSOD3-2A, and TaSOD3-2D promoters, while TaWRKY10 binds to the W-box, and TaSOD3-2A promoter. These findings highlight a synergistic mechanism by which TaRAP2-13L and TaWRKY10 regulate drought tolerance, offering potential targets for improving drought tolerance in wheat through transgenic strategies.

Genome-wide identification and expression analysis of the DREB gene family in foxtail millet (Setaria Italica L.)

BACKGROUND

Dehydration response element binding factors (DREBs) are a family of plant-specific transcription factors that regulate plant responses.

RESULTS

In this study, members of the SiDREB gene family were identified and analyzed in terms of their physicochemical properties, phylogeny, and structure of the encoded proteins. The expression patterns of the DREB transcription factors in foxtail millet under stress were analysed by combining the qRT-PCR data for foxtail millet after exposure to low temperature, abscisic acid (ABA), and osmotic stress (20% PEG 6000). There were 56 SiDREB genes, which were divided into six subgroups, that were located on nine chromosomes of foxtail millet. Chromosomal localization showed that the SiDREB genes were unevenly distributed across nine foxtail millet chromosomes. Furthermore, qRT‒PCR experiments revealed that 19 SiDREB genes play a role in the response to abiotic stress and ABA.

CONCLUSIONS

The results of this study lay a foundation for further research on the functions of the DREB genes in foxtail millet and will be beneficial foe the genetic improvement of this species.

Identification of the regulatory role of SsMYBS25-4 in salt stress from MYB-related transcription factors in sugarcane (Saccharum spontaneum)

Sugarcane is a highly valued crop known for its significant production of sugar and biomass. MYB transcription factors (TFs) are critical regulators in plant growth and stress tolerance, but MYB-related genes, an atypical subset of the MYB family, remain less explored. In this study, we identified 119 MYB-related genes in the genome of wild sugarcane (S. spontaneum). We thoroughly investigated their phylogenetic relationships, chromosomal locations, motif compositions, and three-dimensional (3D) protein structures by bioinformatic methods. Moreover, the expression patterns of these genes demonstrated significant diversity in plant growth and under salt stress. One of the genes, SsMYBS25-4, exhibited a significantly up-regulated expression in response to salt stress and was selected for further functional elucidation. It was found that the overexpression (OE) of SsMYBS25-4 in Arabidopsis can improve the salt stress tolerance of transgenic plants. Interestingly, the expression of some marker genes related to salt stress was significantly up-regulated in OE plants compared to wide-type plants. The SsMYB25-4 protein was localized in the nucleus and was proven to be directly bound to the promoter of the AtDR29B gene. We proposed a mechanism for SsMYB25-4 that enhances salt stress tolerance, contributing to the understanding and application of MYB-related genes in sugarcane breeding.

Genome-wide analysis and functional validation of the cotton FAH gene family for salt stress

BACKGROUND

Fatty acid hydroxylases (FAHs) are a family of enzymes that includes fatty acid hydroxylases, carotenoid hydroxylases, and sterol desaturases. Fatty acids are highly important for plants. They are the main source of energy storage and the main component of the cell membrane. Saturated fatty acids can be divided into two categories: saturated fatty acids and unsaturated fatty acids. FAHs play a pivotal role in enhancing plant salt tolerance by modulating fatty acid metabolic pathways, thereby improving cell membrane stability and antioxidant capacity.

RESULTS

In this study, we identified a total of 129 FAH gene family members in four cotton species, namely, Gossypium hirsutum, Gossypium darwinii, Gossypium arboreum, and Gossypium raimondii. The FAH genes were divided into five subgroups via evolutionary analysis. FAH genes located in the same subgroup presented similar gene structures and a consistent distribution of conserved motifs through the analysis of evolutionary trees, gene structures, and conserved motifs. Chromosomal localization analysis of the FAH gene family revealed that it has undergone chromosomal segment duplication events. Analysis of cis-acting elements suggested that the FAH gene may be involved in regulating biotic and abiotic stresses, plant growth and development, signaling pathways, and other physiological processes. The RT‒qPCR results revealed significant differences in the expression levels of FAH gene family members under salt stress conditions compared with those in the control group. Additionally, we successfully silenced Gohir.A03G045300 through VIGS experiments, and the results indicated that the silenced plants were more sensitive to salt stress than the control plants were. This suggests that Gohir.A03G045300 may be involved in the response of cotton to salt stress.

CONCLUSIONS

A total of 129 FAH genes were identified in four Gossypium species through bioinformatics analysis. Gene silencing of FAH members in G. hirsutum revealed that the FAH gene family plays a crucial role in the response of cotton to salt stress.

Identification and functional characterization of MYB genes regulating polyphenol biosynthesis in cabbage for resistance to Xanthomonas campestris pv. campestris

Cabbage (Brassica oleracea L. var. capitata) is a vital leafy vegetable, but its production is frequently impacted by Xanthomonas campestris pv. campestris (Xcc). The MYB family is one of the most abundant families involved in plant responses to biotic stresses. However, genome-wide identification of MYB and their roles in regulating phenolic synthesis during Xcc resistance have not been previously reported in cabbage. The present investigation reports a total of 322 BoMYB genes. Transcriptome data revealed that 37 BoMYBs were significantly upregulated upon Xcc infection. Concurrently, an increase in polyphenol content was observed, suggesting a pivotal role of polyphenols in Xcc resistance. Based on phylogenetic relationships and qRT-PCR analysis, BoMYB108 was identified as a candidate gene potentially involved in early resistance to Xcc by regulating polyphenol biosynthesis. Overexpression and silencing experiments were conducted to validate the function of BoMYB108. Overexpression of BoMYB108 significantly enhanced the accumulation of phenolic acids, while silencing resulted in the opposite effect. Furthermore, increased phenolic acid levels were associated with reduced reactive oxygen species (ROS) accumulation. These findings indicate that BoMYB108 promotes phenolic acid biosynthesis and mitigates ROS accumulation under Xcc stress, thereby alleviating Xcc-induced damage. In summary, this study provides a valuable data resource for the MYB gene family in cabbage and establishes a theoretical foundation for understanding the phenolic-based mechanisms of Xcc resistance in brassicaceous vegetables.

Systematic identification of R2R3-MYB S6 subfamily genes in Brassicaceae and its role in anthocyanin biosynthesis in Brassica crops

The Brassicaceae family includes Arabidopsis thaliana, various vegetables and oil crops. The R2R3-MYB genes of the S6 subfamily are crucial for regulating anthocyanin biosynthesis, however, their systematic identification in Brassicaceae plants is still incomplete. Here, we systematically identified homologous genes of R2R3-MYB transcription factors from the S6 subfamily across 31 Brassicaceae species. A total of 92 homologous genes were identified, with species representation ranging from 0 to 10 genes per species. Phylogenetic analysis classified these homologous genes into six distinct groups. Notably, approximately 70% of the homologous genes were found within the G6 group, indicating a high degree of evolutionary conservation. Furthermore, a phylogenetic analysis was conducted on 35 homologous genes obtained from six species within the U's triangle Brassica plants. The findings provided evidence of significant conservation among orthologous genes across species and demonstrated strong collinearity on subgenomic chromosomes, with notable tandem duplications observed on chromosomes A7 and C6. Subsequently, we predicted the cis-acting elements of these 35 homologous genes, and analyzed their structures, conserved motifs, and characteristic conserved domains, confirming the significant similarities between orthologous genes. Additionally, we employed white and purple flower rapeseed specimens to conduct qRT-PCR validation of the key genes and transcriptional regulators associated with the anthocyanin synthesis pathway. The results revealed significant differential expression of BnaPAP2.A7.b in purple flowers, alongside the differential expression of BnaPAP2.C6.d. Ultimately, based on previous research and the findings of this study, we propose a transcriptional regulatory framework to govern anthocyanin accumulation in distinct tissues or organs of B. napus. Our findings offer a novel perspective on the functional diversification of R2R3-MYB transcription factors within the S6 subfamily homologous genes, while also shedding light on the regulatory network governing anthocyanin biosynthesis in Brassicaceae species.

Identification of Aldehyde Dehydrogenase Gene Family in Glycyrrhiza uralensis and Analysis of Expression Pattern Under Drought Stress

Aldehyde dehydrogenases (ALDHs) are a gene family that relies on NAD +/NADP + proteins to oxidize toxic aldehydes to non-toxic carboxylic acids, and they play a crucial role in the growth and development of plants, as well as in their ability to withstand stress. This study identified 26 ALDH genes from six Glycyrrhiza uralensis gene families distributed on six chromosomes. By analyzing the phylogeny, gene structure, conserved motifs, cis-regulatory elements, collinearity of homologs, evolutionary patterns, differentiation patterns, and expression variations under drought stress, we found that the ALDH gene is involved in phytohormones and exhibits responsiveness to various environmental stressors by modulating multiple cis-regulatory elements. In addition, GuALDH3H1, GuALDH6B1, GuALDH12A2, and GuALDH12A1 have been identified as playing a crucial role in the response to drought stress. By analyzing the expression patterns of different tissues under drought stress, we discovered that GuALDH3I2 and GuALDH2B2 exhibited the most pronounced impact in relation to the drought stress response, which indicates that they play a positive role in the response to abiotic stress. These findings provide a comprehensive theoretical basis for the ALDH gene family in Glycyrrhiza uralensis and enhance our understanding of the molecular mechanisms underlying ALDH genes in licorice growth, development, and adaptation to drought stress.

Comparative Transcriptome Analysis of Two Types of Rye Under Low-Temperature Stress

Wheat is a crucial food crop, and low-temperature stress can severely disrupt its growth and development, ultimately leading to a substantial reduction in wheat yield. Understanding the cold-resistant genes of wheat and their action pathways is essential for revealing the cold-resistance mechanism of wheat, enhancing its yield and quality in low-temperature environments, and ensuring global food security. Rye (Secale cereale L.), on the other hand, has excellent cold resistance in comparison to some other crops. By studying the differential responses of different rye varieties to low-temperature stress at the transcriptome level, we aim to identify key genes and regulatory mechanisms related to cold tolerance. This knowledge can not only deepen our understanding of the molecular basis of rye's cold resistance but also provide valuable insights for improving the cold tolerance of other crops through genetic breeding strategies. In this study, young leaves of two rye varieties, namely "winter" rye and "victory" rye, were used as experimental materials. Leaf samples of both types were treated at 4 °C for 0, 6, 24, and 72 h and then underwent RNA-sequencing. A total of 144,371 Unigenes were reconstituted. The Unigenes annotated in the NR, GO, KEGG, and KOG databases accounted for 79.39%, 55.98%, 59.90%, and 56.28%, respectively. A total of 3013 Unigenes were annotated as transcription factors (TFs), mainly belonging to the MYB family and the bHLH family. A total of 122,065 differentially expressed genes (DEGs) were identified and annotated in the GO pathways and KEGG pathways. For DEG analysis, 0 h 4 °C treated samples were controls. With strict criteria (p < 0.05, fold-change > 2 or <0.5, |log2(fold-change)| > 1), 122,065 DEGs were identified and annotated in GO and KEGG pathways. Among them, the "Chloroplast thylakoid membrane" and "Chloroplast" pathways were enriched in both the "winter" rye and "victory" rye groups treated with low temperatures, but the degrees of significance were different. Compared with "victory" rye, "winter" rye has more annotated pathways such as the "hydrogen catabolic process". Although the presence of more pathways does not directly prove a more extensive cold-resistant mechanism, these pathways are likely associated with cold tolerance. Our subsequent analysis of gene expression patterns within these pathways, as well as their relationships with known cold-resistance-related genes, suggests that they play important roles in "winter" rye's response to low-temperature stress. For example, genes in the "hydrogen catabolic process" pathway may be involved in regulating cellular redox balance, which is crucial for maintaining cell function under cold stress.

gma-miR828a Negatively Regulates Resistance to Tea Leaf Spot Caused by Lasiodiplodia theobromae Through Targeting the CsMYB28-CsRPP13 Module

Leaf spot caused by the fungus Lasiodiplodia theobromae severely affects the quality and production of tea (Camellia sinensis) in plantations across southwestern China. Currently, no effective control measures are available, and the damage to tea leaves is also exacerbated by a lack of understanding regarding the epidemiology of the disease. Previous studies have suggested that gma-miR828a is differentially expressed during L. theobromae infection and may target and cleave the mRNA of CsMYB28. In this study, we characterised CsMYB28 as encoding a transcription factor (TF) that localises to the nucleus, cell membrane, and cytoplasm. This gene was found to be differentially and spatiotemporally expressed in leaf tissues following L. theobromae infection of leaves of the tea plant. Altered CsMYB28 expression, achieved by transient overexpression or stable genetic transformation of Nicotiana benthamiana, or transient silencing using antisense oligonucleotides (AsODN) in the tea plant, indicated that CsMYB28 contributes to resistance against L. theobromae. Using DNA affinity purification sequencing, yeast one-hybrid, and dual-luciferase assays, we also identified that CsMYB28 bound to the AATTAATT motif of CsRPP13, thereby activating the expression of CsRPP13. Additionally, degradome sequencing, β-glucuronidase (GUS) assays, and RNA ligase-mediated rapid amplification of cDNA ends revealed that miR828a cleaved CsMYB28 mRNA, negatively regulating its expression. The results from transient overexpression and stable transformation studies, combined with AsODN-mediated silencing in the tea plant, suggested that miR828a plays a negative regulatory role in modulating the response of the tea plant to L. theobromae infection. This study demonstrates that the miR828a-CsMYB28-CsRPP13 mediates the response of the tea plant to L. theobromae infection.

Chromosome-level genome assembly of Pontederia cordata L. provides insights into its rapid adaptation and variation of flower colours

Pontederia cordata L. is an aquatic ornamental plant native to the Americas but has been widely distributed in South Asia, Australia, and Europe. The genetic mechanisms behind its rapid adaptation and spread have not yet been well understood. To understand the mechanisms for its rapid adaptation, this study assembled the first chromosome-level genome of P. cordata. The genome assembly, which spans 527.5 Mb, is anchored on 8 pseudochromosomes with a scaffold N50 of 48 Mb and encompasses 29,389 protein-coding genes. Further analyses revealed that P. cordata had experienced 3 whole-genome duplications (WGDs) events. These WGDs are associated with gene family expansion and increased numbers of resistance gene analogs and transcription factors. Positive selection analysis indicated that genes derived from tandem duplication (TD) and proximal duplication were more likely to undergo positive selection, and were enriched in plant defense and disease resistance. These results implied that WGDs, TD, and positive selection enhanced the environmental adaptability of P. cordata. In addition, we found that down-regulation of F3'5'H, DFR, ANS, and UFGT likely caused the flower colour variation for P. cordata from violet to white. The first chromosome-level genome of P. cordata here provides a valuable genomic resource for investigating the rapid adaptation and flower colour variation of the species.

PLATZ transcription factors and their emerging roles in plant responses to environmental stresses

Plant A/T-rich sequence- and zinc-binding (PLATZ) family proteins represent a novel class of plant-specific transcription factors that bind to A/T-rich sequences. Advances in high-throughput sequencing and bioinformatics analyses have facilitated the identification of numerous PLATZ proteins across various plant species. Over the last decade, accumulating evidence from omics analyses, genetics studies, and gain- and loss-of function investigations has indicated that PLATZ proteins play crucial roles in the complex regulatory networks governing plant development and adaptation to environmental stress. Recently, an excellent review has been published highlighting the roles of PLATZ proteins in controlling plant developmental processes. However, a comprehensive review specifically addressing the molecular mechanisms by which these proteins drive their functions in plant responses to environmental cues is currently lacking. In this review, we summarize the characteristics and identification of PLATZ proteins, emphasizing their significance in stress responses. We also highlight the crosstalk between PLATZ proteins and phytohormones. Furthermore, we discuss the downstream target genes, interacting partners, and upstream regulatory mechanisms associated with PLATZ proteins, providing a thorough understanding of their multifaceted roles in plants.

Identification, characterization, and expression of Oryza sativa tryptophan decarboxylase genes associated with fluroxypyr-meptyl metabolism

Tryptophan decarboxylase (TDC) belongs to a family of aromatic amino acid decarboxylases and catalyzes the conversion of tryptophan to tryptamine. It is the enzyme involved in the first step of melatonin (MT) biosynthesis and mediates several key functions in abiotic stress tolerance. In Oryza sativa under pesticide-induced stress, TDC function is unclear. Three TDC differentially expressed genes (DEGs) and six TDC-coding genes were found to be expressed in fluroxypyr-meptyl (FLUME)-treated rice transcriptome datasets, which allowed researchers to explore the properties and roles of rice TDC family genes under pesticide-induced stress. By applying sequence alignment and phylogenetic analysis, two subfamilies of the TDC gene family-DUF674 and AAT_I-were found in rice, Glycine max, Zea mays, Hordeum vulgare, and Solanum lycopersicum. According to chromosomal location studies, segmental duplication aided in the expansion of the OsTDC gene family, and the three TDC DEGs in rice were irregularly distributed on two of its 12 chromosomes. In addition, nine rice TDC genes displayed a collinear relationship with those of soybean, maize, barley, and tomato. Rice TDC genes can encode a variety of biotic and abiotic stress responses because of their diverse gene architectures, cis-elements, motif compositions, and conserved domains. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis confirmed that a proportion of TDC genes (Os08g0140300, Os08g0140500, and Os10g0380800) were preferably expressed under 0.08 mg L-1 FLUME stress, with a 5.2-, 3.2-, and 3.9-fold increase in roots and a 2.1-, 2.4-, and 2.6-fold increase in shoots, respectively. MT treatment further increased the expression of these genes, with a 2.1-fold, 3.1-fold, and fivefold increase in roots and a 1.5-, 1.1-, and 1.1-fold increase in shoots than that treated with 0.08 mg L-1 FLUME only, respectively. When rice seedling roots and shoots were subjected to 0.08 mg L-1 FLUME stress, TDC activity was increased by 2.7 and 1.6 times higher than in the control, respectively. MT application also further promoted TDC activity in rice tissues; TDC activity in rice roots and shoots was twofold and 1.4-fold higher, respectively, than that under 0.08 mg L-1 FLUME alone. These findings indicate that TDC genes respond effectively to FLUME stress, and the application of MT could enhance the expression of these TDC genes, which comprise a set of candidate genes that regulate pesticide metabolism and degradation with the application of MT.

Endophytic entomopathogenic fungi enhance plant immune responses against tomato leafminer

Plants employ various defense mechanisms to protect themselves from invaders such as microorganisms and herbivores. By recognizing these threats, plants can trigger a cascade of responses throughout their tissues, effectively priming their defenses and enhancing their resistance to future attacks. In this study, we examined the indirect effects of the entomopathogenic fungi Beauveria bassiana strain GHA and Metarhizium anisopliae strain F01 on tomato growth, expression of selected plant genes, production of secondary metabolites, and preference and performance of the tomato leafminer (Tuta absoluta). Both B. bassiana and M. anisopliae colonized tomato endophytically. Plants treated with B. bassiana had greater biomass than the untreated control and M. anisopliae treated plants. Oviposition was lower on plants treated with B. bassiana and M. anisopliae than on untreated controls in both choice and no-choice studies, and both endophytic EPF also affected the development of leafminer larvae. Gene expression analysis of tomato leaves inoculated with endophytic EPF provided evidence of triggering plant immune response genes, and of priming genes for herbivore attack, making plants more resistant to herbivory. These findings provide important insights into the mechanisms by which B. bassiana and M. anisopliae promote tomato plant growth and rapidly respond to T. absoluta infestation by priming the immune system. This knowledge could improve the development of entomopathogenic fungi for use in plant-protection strategies.

The 1R-MYB transcription factor SlMYB1L modulates drought tolerance via an ABA-dependent pathway in tomato

The MYB transcription factor family is one of the biggest transcription factors in plants, playing key roles in regulating many biological processes, including growth and development, responses to biotic and abiotic stresses and hormone signaling. In this study, we identified and characterized an 1R-MYB transcription factor, SlMYB1L, which is involved in regulating drought tolerance in tomato. SlMYB1L-RNAi transgenic plants displayed more severe dehydration phenotype with elevated malondiadehyde (MDA) and hydrogen peroxide (H2O2), as well as reduced proline content and antioxidant enzyme activities compared to wild-type under drought stress. Additionally, SlMYB1L influenced drought-induced stomatal closure and modulated endogenous ABA levels, leading to a decrease in the expression of ABA-related genes in SlMYB1L-RNAi transgenic plants. A dual-luciferase reporter assay further confirmed that SlMYB1L represses the expression of ABA catabolism gene SlCYP707A3. In conclusion, our findings suggest that SlMYB1L is a stress-responsive transcription factor that positively regulates drought tolerance and may serve as a candidate gene for developing drought-resistant crops.

CRISPR-Cas9-mediated deletions of FvMYB46 in Fragaria vesca reveal its role in regulation of fruit set and phenylpropanoid biosynthesis

The phenylpropanoid pathway, regulated by transcription factors of the MYB family, produces secondary metabolites that play important roles in fertilization and early phase of fruit development. The MYB46 transcription factor is a key regulator of secondary cell wall structure, lignin and flavonoid biosynthesis in many plants, but little is known about its activity in flowers and berries in F. vesca. For functional analysis of FvMYB46, we designed a CRISPR-Cas9 construct with an endogenous F. vesca-specific U6 promoter for efficient and specific expression of two gRNAs targeting the first exon of FvMYB46. This generated mutants with an in-frame 81-bp deletion of the first conserved MYB domain or an out-of-frame 82-bp deletion potentially knocking out gene function. In both types of mutant plants, pollen germination and fruit set were significantly reduced compared to wild type. Transcriptomic analysis of flowers revealed that FvMYB46 positively regulates the expression of genes involved in processes like xylan biosynthesis and metabolism, homeostasis of reactive oxygen species (ROS) and the phenylpropanoid pathway, including secondary cell wall biosynthesis and flavonoid biosynthesis. Genes regulating carbohydrate metabolism and signalling were also deregulated, suggesting that FvMYB46 might regulate the crosstalk between carbohydrate metabolism and phenylpropanoid biosynthesis. In the FvMYB46-mutant flowers, the flavanol and flavan-3-ol contents, especially epicatechin, quercetin-glucoside and kaempferol-3-coumaroylhexoside, were reduced, and we observed a local reduction in the lignin content in the anthers. Together, these results suggest that FvMYB46 controls fertility and efficient fruit set by regulating the cell wall structure, flavonoid biosynthesis, carbohydrate metabolism, and sugar and ROS signalling in flowers and early fruit development in F. vesca.

Identification of Key Pathways and Candidate Genes Controlling Organ Size Through Transcriptome and Weighted Gene Co-Expression Network Analyses in Navel Orange Plants (Citrus sinensis)

Background/Objectives: Organ size is a critical target trait in fruit-tree breeding programs, as it significantly impacts the economic value of plants by influencing their biomass, yield, and quality. Understanding the molecular mechanisms underlying organ size in citrus is essential for breeding new cultivars with superior fruit quality. Methods: In this study, we investigated the regulatory network involved in organ size using the Citrus sinensis 'Newhall' navel orange variety and its large-organ mutant, 'M25'. Results: Ploidy analysis indicated that the organ enlargement observed in 'M25' was not attributable to changes in chromosome ploidy. Furthermore, RNA sequencing of tender leaves and young fruits from both 'M25' and 'Newhall' oranges identified 1817 and 1605 differentially expressed genes (DEGs), respectively. Functional enrichment analysis revealed that these DEGs were enriched in pathways associated with organ size regulation, including those related to cell division, DNA replication, protein biosynthesis, plant hormone signal transduction, and cell wall metabolism. Weighted gene co-expression network analysis identified the grey 60 and orange modules as the key modules influencing organ enlargement; from these modules, we identified 51 and 35 hub genes, respectively. Combined homologous function annotation and expression analysis identified four transcription-factor-encoding hub genes (Cs_ont_6g005380, Cs_ont_8g025330, Cs_ont_9g019400, and Cs_ont_9g008010) as candidate genes potentially related to organ size. Conclusions: Among these, Cs_ont_8g025330 (CsMYB73) was inferred to be the key gene influencing organ size through auxin and cytokinin regulation. These findings lay the foundation for further investigations of the regulatory mechanism of organ size in navel orange varieties.

Arabidopsis thaliana Plants' Overexpression of the MYB Transcription Factor VhMYB60 in the Face of Stress Hazards Enhances Salt and Cold Tolerance

'Beta' (Vitisriparia × V. labrusca) is a vine fruit tree of the genus Vitis which is a cross between American and riparian grapes. In the current situation of grape production in northern regions, cold, drought, and salinity are important bottlenecks restricting its development, while some grape rootstocks with excellent traits show the disadvantage of poor resilience. 'Beta' (Vitis riparia × V. labrusca), one of the most extensively utilized rootstocks in viticulture, has demonstrated remarkable resilience to adverse conditions. However, the mechanisms by which 'Beta' rootstocks resist abiotic stresses are unknown and need to be further investigated. In this study, we successfully isolated and cloned a novel MYB transcription factor, VhMYB60, from the 'Beta' grapevine. This factor spans 972 base pairs and encodes a protein comprising 323 amino acids. Subcellular localization studies revealed that VhMYB60 is predominantly expressed within the nucleus. Furthermore, tissue-specific expression analysis demonstrated that VhMYB60 is more abundantly expressed in the mature leaves and roots of the grape plant. Further studies showed that salt and cold stress notably increased VhMYB60 gene expression in both mature leaves and grape roots. Compared with the control, Arabidopsis thaliana (Arabidopsis) plants molecularly modified to overexpress VhMYB60 exhibited enhanced salt and cold resistance and improved survival rates. Moreover, notable changes were detected in chlorophyll, malondialdehyde (MDA), proline, peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) levels. Concurrently, the expression levels of structural genes that are positively correlated with resistance to adversity stress were markedly elevated in Arabidopsis plants that overexpress VhMYB60. Consequently, VhMYB60 may serve as a pivotal transcription factor in the regulation of 'Beta' resistance.

The Transcription Factor CcMYB330 Regulates Capsaicinoid Biosynthesis in Pepper Fruits

Pepper is an important vegetable and economic crop, and the MYB family is one of the most numerous transcription factor families in plants, extensively participating in various biological processes such as plant growth, development, and stress resistance. In this study, CcMYB330 is identified as a differentially expressed gene in the pepper fruit, and CcMYB330 is expressed with higher expression levels in the placenta and pericarp at different development stages of pepper fruit. Analysis of the promoter cis-elements revealed that this gene contains not only core elements but also environmental factor response elements and plant hormone response elements. The silencing of CcMYB330 could reduce the capsaicinoid accumulation in pepper fruit, while the overexpression of CcMYB330 could increase capsaicinoid accumulation. Additionally, silencing or overexpressing CcMYB330 could regulate the expression of structural genes involved in capsaicinoid biosynthesis. In addition, through yeast one-hybrid experiments, we identified an interaction between CcMYB330 and the capsaicinoid biosynthesis structural gene CcPAL. Further evidence from EMSA experiments and dual luciferase assays confirmed that CcMYB330 can bind to the cis-element ACCAACAACCAAA in the CcPAL promoter. These results indicate that CcMYB330 may regulate the synthesis of capsaicinoids by modulating structural genes in the capsaicinoid biosynthesis pathway, providing new insights into the regulatory mechanisms of capsaicinoid synthesis.

Genome-Wide Identification, Characterization, and Expression Analysis of BES1 Family Genes in 'Tieguanyin' Tea Under Abiotic Stress

The BRI1-EMS-SUPPRESSOR 1 (BES1) family comprises plant-specific transcription factors, which are distinguished by atypical bHLH domains. Over the past two decades, genetic and biochemical studies have established that members of the BRI1-EMS-SUPPRESSOR 1 (BES1) family are crucial for regulating the expression of genes involved in brassinosteroid (BR) response in rapeseed. Due to the significance of the BES1 gene family, extensive research has been conducted to investigate its functional properties. This study presents a comprehensive identification and computational analysis of BES1 genes in 'Tieguanyin' (TGY) tea (Camellia sinensis). A total of 10 BES1 genes were initially identified in the TGY genome. Through phylogenetic tree analysis, this study uniquely revealed that CsBES1.2 and CsBES1.5 cluster with SlBES1.8 from Solanum lycopersicum, indicating their critical roles in fruit growth and development. Synteny analysis identified 20 syntenic genes, suggesting the conservation of their evolutionary functions. Analysis of the promoter regions revealed two types of light-responsive cis-elements, with CsBES1.4 exhibiting the highest number of light-related cis-elements (13), followed by CsBES1.9 and CsBES1.10. Additional validation via qRT-PCR experiments showed that CsBES1.9 and CsBES1.10 were significantly upregulated under light exposure, with CsBES1.10 reaching approximately six times the expression level of the control after 4 h. These results suggest that CsBES1.9 and CsBES1.4 could play crucial roles in responding to abiotic stress. This study offers novel insights into the functional roles of the BES1 gene family in 'Tieguanyin' tea and establishes a significant foundation for future research, especially in exploring the roles of these genes in response to abiotic stresses, such as light exposure.

Genome-wide identification and comparative analysis of the AP2/ERF gene family in Prunus dulcis and Prunus tenella: expression of PdAP2/ERF genes under freezing stress during dormancy

The AP2/ERF (APETALA2/ethylene responsive factor) transcription factor family, one of the largest in plants, plays a crucial role in regulating various biological processes, including plant growth and development, hormone signaling, and stress response. This study identified 114 and 116 AP2/ERF genes in the genomes of 'Wanfeng' almond (Prunus dulcis) and 'Yumin' wild dwarf almond (Prunus tenella), respectively. These genes were categorized into five subfamilies: AP2, DREB, ERF, RAV, and Soloist. The PdAP2/ERF and PtAP2/ERF members both demonstrated high conservation in protein motifs and gene structures. Members of both families were unevenly distributed across eight chromosomes, with 30 and 27 pairs of segmental duplications and 15 and 18 pairs of tandem repeated genes, respectively. The promoter regions of PdAP2/ERF and PtAP2/ERF family members contained numerous important cis-elements related to growth and development, hormone regulation, and stress response. Expression pattern analysis revealed that PdAP2/ERF family members exhibited responsive characteristics under freezing stress at different temperatures in perennial dormant branches. Quantitative fluorescence analysis indicated that PdAP2/ERF genes might be more intensely expressed in the phloem of perennial dormant branches of almond, with the opposite trend observed in the xylem. This study compared the characteristics of PdAP2/ERF and PtAP2/ERF gene family members and initially explored the expression patterns of PdAP2/ERF genes in the phloem and xylem of perennial dormant branches. The findings provide a theoretical foundation for future research on almond improvement and breeding, as well as the molecular mechanisms underlying resistance to freezing stress.

Comparative transcriptome and metabolome analysis reveals the differential response to salinity stress of two genotypes brewing sorghum

Salinity tolerance in brewing sorghum is a very important trait, especially in areas that are affected by soil salinity. In order to elucidate the mechanism underlying salt tolerance, we conducted a comparative analysis of the transcriptome and metabolome in two distinct sweet sorghum genotypes, namely the salt-tolerant line NY1298 and the salt-sensitive line MY1176, following exposure to salt treatment. Our initial findings indicate the presence of genotype-specific responses in brewing sorghum under salt stress conditions. Notably, there were variations in the expression of genes and metabolites among different genotypes in response to high-salt stress. Specifically, certain transcription factors belonging to the WRKY, MYB, and NAC families were identified as being involved in the response to increased external salinity. WGCNA analysis identified stage-specific gene expression for different salinity gradients in each cultivar, and explored the gene function by KEGG enrichment analysis. Combined analysis of DEGs and DEMs in hormone synthesis found AUX/IAA, SAUR, CRE1, A-ARR, PP2C, SNRK2 genes, and 3-indoleacetic acid and jasmonic acid were evidently differential expression among different salt concentrations. Taken together, our study carried out a comprehensive overview of two genotypes of brewing sorghum gene and metabolite expression differences in response to salt stress, and expanded the understanding of responsive mechanism of brewing sorghum to salt stress.

Utilizing physiologies, transcriptomics, and metabolomics to unravel key genes and metabolites of Salvia miltiorrhiza Bge. seedlings in response to drought stress

Drought stress inhibits Salvia miltiorrhiza Bunge (S. miltiorrhiza) seedling growth and yield. Here, we studied the effects of drought stress on the different parts of S. miltiorrhiza seedlings through physiological, transcriptomic, and metabolomics analyses, and identified key genes and metabolites related to drought tolerance. Physiological analysis showed that drought stress increased the accumulation of hydrogen peroxide (H2O2), enhanced the activity of peroxidase (POD), decreased the activity of catalase (CAT) and the contents of chlorophyll b and total chlorophyll, reduced the degree of photosynthesis, enhanced oxidative damage in S. miltiorrhiza seedlings, and inhibited the growth of S. miltiorrhiza plants. Transcriptome analyses revealed 383 genes encoding transcription factors and 80 genes encoding plant hormones as hypothetical regulators of drought resistance in S. miltiorrhiza plants. Moreover, differentially expressed genes (DEGs) and differentially expressed metabolites (DEMs) are involved in a variety of biological processes, such as proline and glycine betaine metabolism, and biosynthesis of tanshinones and phenolic acids. Additionally, it has barely been reported that the AHL gene family may be involved in regulating the neocryptotanshinone biosynthesis. In conclusion, our results suggest that drought stress inhibits S. miltiorrhiza seedling growth by enhancing membrane lipid peroxidation, attenuating the antioxidant system, photosynthesis, and regulating proline and glycine betaine metabolism, transcription factors and plant hormones, and tanshinones and phenolic acid metabolism pathways. This study provides new insights into the complex mechanisms by which S. miltiorrhiza responds to drought stress.

Integrative metabolomics and transcriptomics profiling reveals differential expression of flavonoid synthesis in Ophiopogon japonicus (L. f.) Ker-Gawl. in adaptation to drought

Drought is one of the consequences of climate change that severely affects plant growth and development. Ophiopogon japonicus (L. f.) Ker-Gawl. (Chinese name: Chuanmaidong, abbreviated as CMD) is a commonly used herbaceous plant whose growth and development are strongly affected by drought. Here, we comprehensively analyzed the transcriptomic and metabolic responses of two CMD varieties (EP and CP) to drought stress. CP utilized a small number of differentially expressed genes to regulate a greater number of differential metabolites compared to EP, suggesting that it may be more drought tolerant. In addition, integrated transcriptome and metabolome analyses revealed that transcription factors such as WRKY, TIFY, and C2H2 regulate flavonoid synthesis in CMD. These findings provide ideas for in-depth analysis of the mechanism of CMD against drought stress, and provide a theoretical basis for breeding high-quality drought-tolerant varieties.

WRKY Transcription Factors Modulate the Flavonoid Pathway of Rhododendron chrysanthum Pall. Under UV-B Stress

The depletion of the ozone layer has resulted in elevated ultraviolet-B (UV-B) radiation levels, posing a significant risk to terrestrial plant growth. Rhododendron chrysanthum Pall. (R. chrysanthum), adapted to high-altitude and high-irradiation environments, has developed unique adaptive mechanisms. This study exposed R. chrysanthum to UV-B radiation for two days, with an 8 h daily treatment, utilizing metabolomic and transcriptomic analyses to explore the role of WRKY transcription factors in the plant's UV-B stress response and their regulation of flavonoid synthesis. UV-B stress resulted in a significant decrease in rETR and Ik and a significant increase in 1-qP. These chlorophyll fluorescence parameters indicate that UV-B stress impaired photosynthesis in R. chrysanthum. Faced with the detrimental impact of UV-B radiation, R. chrysanthum is capable of mitigating its effects by modulating its flavonoid biosynthetic pathways to adapt positively to the stress. This study revealed changes in the expression of 113 flavonoid-related metabolites and 42 associated genes, with WRKY transcription factors showing significant correlation with these alterations. WRKY transcription factors can influence the expression of key enzyme genes in the flavonoid metabolic pathway, thereby affecting metabolite production. A theoretical reference for investigating plant stress physiology is provided in this work, which also offers insights into the stress responses of alpine plants under adverse conditions.

Modification of xylan in secondary walls alters cell wall biosynthesis and wood formation programs and improves saccharification

Wood of broad-leaf tree species is a valued source of renewable biomass for biorefinery and a target for genetic improvement efforts to reduce its recalcitrance. Glucuronoxylan (GX) plays a key role in recalcitrance through its interactions with cellulose and lignin. To reduce recalcitrance, we modified wood GX by expressing GH10 and GH11 endoxylanases from Aspergillus nidulans in hybrid aspen (Populus tremula L. × tremuloides Michx.) and targeting the enzymes to cell wall. The xylanases reduced tree height, modified cambial activity by increasing phloem and reducing xylem production, and reduced secondary wall deposition. Xylan molecular weight was decreased, and the spacing between acetyl and MeGlcA side chains was reduced in transgenic lines. The transgenic trees produced hypolignified xylem having thin secondary walls and deformed vessels. Glucose yields of enzymatic saccharification without pretreatment almost doubled indicating decreased recalcitrance. The transcriptomics, hormonomics and metabolomics data provided evidence for activation of cytokinin and ethylene signalling pathways, decrease in ABA levels, transcriptional suppression of lignification and a subset of secondary wall biosynthetic program, including xylan glucuronidation and acetylation machinery. Several candidate genes for perception of impairment in xylan integrity were detected. These candidates could provide a new target for uncoupling negative growth effects from reduced recalcitrance. In conclusion, our study supports the hypothesis that xylan modification generates intrinsic signals and evokes novel pathways regulating tree growth and secondary wall biosynthesis.

TaWRKY55-TaPLATZ2 module negatively regulate saline-alkali stress tolerance in wheat

Saline-alkaline soils are a major environmental problem that limit plant growth and crop productivity. Plasma membrane H+-ATPases and the salt overly sensitive (SOS) signaling pathway play important roles in plant responses to saline-alkali stress. However, little is known about the functional genes and mechanisms regulating the transcription of H+-ATPases and SOS pathway genes under saline-alkali stress. In the present study, we identified that the plant AT-rich sequence and zinc-binding (TaPLATZ2) transcription factor are involved in wheat response to saline-alkali stress by directly suppressing the expression of TaHA2/TaSOS3. The knockdown of TaPLATZ2 enhances salt and alkali stress tolerance, while overexpression of TaPLATZ2 leads to salt and alkali stress sensitivity in wheat. In addition, TaWRKY55 directly upregulated the expression of TaPLATZ2 during saline-alkali stress. Through knockdown and overexpression of TaWRKY55 in wheat, TaWRKY55 was shown to negatively modulate salt and alkali stress tolerance. Genetic analyses confirmed that TaPLATZ2 functions downstream of TaWRKY55 in response to salt and alkaline stresses. These findings provide a TaWRKY55-TaPLATZ2-TaHA2/TaSOS3 regulatory module that regulates wheat responses to saline-alkali stress.

Gene expression modules during the emergence stage of upland cotton under low-temperature stress and identification of the GhSPX9 cold-tolerance gene

Cotton originates from tropical and subtropical regions, and low temperatures are one of the main stress factors restricting its growth, particularly during the seedling stage. However, the mechanism of cold resistance is complex, and the research on gene expression modules under low temperatures during the seedling emergence stage of cotton remains unexplored, and identified vital cold-tolerant genes remain scarce. Here, we revealed the dynamic changes of differentially expressed genes during seed germination under cold stress through transcriptome analysis, with 5140 genes stably differentiating across more than five time points, among which 2826 genes are up-regulated, and 2314 genes are down-regulated. The weighted gene co-expression network analysis (WGCNA) of transcriptome profiles revealed three major cold-responsive modules and identified 98 essential node genes potentially involved in cold response. Genome-wide association analysis further confirmed that the hub gene GhSPX9 is crucial for cold tolerance. Virus-induced gene silencing in cotton demonstrated that GhSPX9 is a positive regulator of cold tolerance in cotton, with interference in its expression significantly enhancing sensitivity to cold stress in germination and seedlings. These results can be applied to identify cold tolerance loci and genes in cotton, promoting research into cold tolerance mechanisms.

MYB4 in Lilium pumilum affects plant saline-alkaline tolerance

Lilium pumilum DC (L. pumilum DC) plays an important role in the rational utilization of salinized soil. To explore the molecular mechanism of salt-tolerant L. pumilum, the LpMYB4 was cloned. LpMYB4 close relationship with Bambusa emeiensis and Zea mays MYB4 throughout the phylogenetic tree construction. LpMYB4 protein was found to be localized in the nucleus. Prokaryotic and eukaryotic bacterial solution resistance experiments proved that the exogenous introduction of LpMYB4 made the overexpression strains obtain better survival ability under saline-alkaline stress. Compared with wild-type plants, tobacco plants overexpressing LpMYB4 had better growth and lower leaf wilting and lodging, the content of chlorophyll was higher, the content of hydrogen peroxide and superoxide anion was lower, the activity of peroxidase and superoxide dismutase was higher and the relative conductivity was lower under saline-alkaline stress. The analysis of seed germination and seedling resistance of transgenic plants under salt stress showed that LpMYB4 transgenic seeds were more tolerant to salt stress during germination and growth. Yeast two-hybrid and two-luciferase complementation experiments showed that LpMYB4 interacted with yeast two-hybrid and LpGPX6. The analysis of the role of LpMYB4 in improving plant saline-alkali resistance is helpful to the transformation of plant germplasm resources and has great significance for agriculture and sustainable development.

GsMYB10 encoding a MYB-CC transcription factor enhances the tolerance to acidic aluminum stress in soybean

BACKGROUND

MYB transcription factors (TFs) play crucial roles in the response to diverse abiotic and biotic stress factors in plants. In this study, the GsMYB10 gene encoding a MYB-CC transcription factor was cloned from wild soybean BW69 line. However, there is less report on the aluminum (Al)-tolerant gene in this subfamily.

RESULTS

The GsMYB10 gene was up-regulated by acidic aluminum stress and rich in the roots with a constitutive expression pattern in soybean. It was found that GsMYB10 protein contains the MYB and coiled-coil (CC) domains, localizes in the nucleus and holds transcriptional activity. The analysis of the transgenic phenotype revealed that the taproot length and root fresh weights of the GsMYB10-OE plants were greater than those of the wild type when subjected to AlCl3 treatments. While the accumulation of Al3+ in root tip of GsMYB10 transgenic plants (59.37 ± 3.59 µg/g) significantly reduced compared with that of wild type (80.40 ± 3.16 µg/g) which were shallowly stained by hematoxylin under the treatments of AlCl3. Physiological indexes showed that the proline content significantly increased 39-45% and the malondialdehyde content significantly reduced 37-42% in GsMYB10-OE plants compared with that of wild type. Transcriptomic analysis showed that overexpression of GsMYB10 induced a large number of differentially expressed genes (DEGs) with Al-treatment, which were related to wall modification related genes included PGs (such as Glyma.19g006200, Glyma.05g005800), XTHs (such as Glyma.12g080100, Glyma.12g101800, Glyma.08g093900 and Glyma.13g322500), NRAMPs and ABCs.

CONCLUSIONS

In summary, the data presented in this paper indicate that GsMYB10, as a new soybean MYB-CC TF, is a positive regulator and increases the adaptability of soybeans to acidic aluminum stress. The findings will contribute to the understanding of soybean response to acidic aluminum stress.

Heterologous Expression of a Potential 'Paulownia fortunei' MYB Factor Gene, PfMYB90, Improves Salt and Cold Tolerance in Arabidopsis

The paulownia tree belongs to the Paulowniaceae family. Paulownia has strong vitality; has strong adaptability to harsh environmental conditions; and can be used as building raw material, as well as processing drugs and having other purposes. In the research field of MYB transcription factors of the paulownia tree, it is rare to discuss the resistance to abiotic stress. The research in this area has not received sufficient attention and depth, which also indicates an important potential direction for future research. In this study, we performed bioinformatics analysis of the stress-related gene PfMYB90, a potential transcription factor, and investigated its mechanism of action under salt and cold stresses. PfMYB90 was strongly expressed in the fully unfolded leaf and root of plants in both stress treatments. Transgenic PfMYB90 Arabidopsis plants had a greater survival rate under salt and cold stresses, and the degree of leaf damage was comparatively smaller, according to phenotypic observation and survival rate calculations. By measuring the corresponding physiological indexes after stress and detecting the expression levels of corresponding stress genes (AtNHX1, AtSOS1, AtSOS2, AtSOS3, AtCBF1, AtCBF3, AtCOR15a, AtRD29a), it was found that after PfMYB90 gene transfer, Arabidopsis showed strong tolerance to salt and cold stresses. This is consistent with the results mentioned above. This transgenic technology enables Arabidopsis to survive under adverse environmental conditions, allowing it to maintain a relatively stable growth state despite salt accumulation and cold stress. Therefore, PfMYB90 may be a key gene in the regulatory network of salt damage and cold damage, as well as one of the key transcription factors for Paulownia fortunei environmental conditions.

Effects of seasonal climates and MIPS1 mutations on soybean germination through multi-omics analysis

This study delves into the combined effects of seasonal climate variations and MIPS1 gene mutations on the germination rates of soybean cultivars TW-1 and TW75. Through comprehensive metabolomic and transcriptomic analyses, we identified key KEGG pathways significantly affected by these factors, including starch and sucrose metabolism, lipid metabolism, and amino acid biosynthesis. These pathways were notably disrupted during the spring, leading to an imbalance in metabolic reserves critical for seedling development. Additionally, MIPS1 gene mutations further altered these pathways, exacerbating the metabolic disturbances. Our results underscore the intricate network of environmental and genetic interactions influencing soybean seed vigor and underscore the importance of understanding these pathways to enhance agricultural resilience and seed quality in fluctuating climates.

Comparative genomics analysis of the MYB gene family in barley: preliminary insights into evolution and biological function in Blue Qingke

Background

The Myeloblastosis related (MYB) family is one of the most widely distributed transcription factor families in plants and plays a significant role in plant growth and development, hormone signal transduction, and stress response. There are many reports on MYB family species, but the research on Qingke is still limited.

Methods

This study used comparative genomics methods to analyze gene and protein structure, protein physicochemical properties, chromosome localization, and evolution. A bioinformatics approach was used to systematically analyze the HvMYB gene family. At the milk stage, soft dough stage, and mature stage, White and Blue Qingke grains were selected for RNA sequencing (RNA-seq), among which two proteins interacted (HvMYB and HvMYC). The expression of this gene family was analyzed through RNA-seq, and the expression levels of HvMYB and HvMYC in the grains of two different color varieties were analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Finally, the interaction between HvMYB and HvMYC was verified by bimolecular fluorescence complementation (BiFC) experiments.

Results

A total of 92 Qingke HvMYB genes were identified and analyzed, and 92 HvMYB proteins were classified into five categories. Cis-acting elements associated with abscisic acid response, light response, and methyl jasmonate (MeJA) response were found in the promoter regions of most MYB genes. Using qRT-PCR combined with RNA-seq analysis showed that MYB gene was highly expressed in the soft dough stage and was varietal specific. Subcellular localization indicated that HvMYB was located in the nucleus and cell membrane, HvMYC was located in the nucleus, cell membrane, and cytoplasm. Through BiFC analysis, it has been proven that HvMYB in the MYB family and HvMYC in the basic helix-loop-helix (bHLH) family can interact. This study provides a preliminary theoretical basis for understanding the function and role of the Qingke MYB gene family and provides a reference for the molecular mechanism of Qingke gene evolution.

The light-harvesting chlorophyll a/b-binding proteins of photosystem II family members are responsible for temperature sensitivity and leaf color phenotype in albino tea plant

INTRODUCTION

Light-harvesting chlorophyll a/b-binding (LHCB) protein complexes of photosystem II are integral to the formation of thylakoid structure and the photosynthetic process. They play an important role in photoprotection, a crucial process in leaf development under low-temperature stress. Nonetheless, potential key genes directly related to low-temperature response and albino phenotype have not been precisely identified in tea plant. Moreover, there are no studies simultaneously investigating multiple albino tea cultivars with different temperature sensitivity.

OBJECTIVES

The study aimed to clarify the basic characteristics of CsLHCB gene family members, and identify critical CsLHCB genes potentially influential in leaf color phenotypic variation and low-temperature stress response by contrasting green and albino tea cultivars. Concurrently, exploring the differential expression of the CsLHCB gene family across diverse temperature-sensitive albino tea cultivars.

METHODS

We identified 20 putative CsLHCB genes according to phylogenetic analysis. Evolutionary relationships, gene duplication, chromosomal localization, and structures were analyzed by TBtools; the physiological and biochemical characteristics were analyzed by protein analysis websites; the differences in coding sequences and protein accumulation in green and albino tea cultivars, gene expression with maturity were tested by molecular biology technology; and protein interaction was analyzed in the STRING database.

RESULTS

All genes were categorized into seven groups, mapping onto 7 chromosomes, including three tandem and one segmental duplications. They all own a conserved chlorophyll A/B binding protein domain. The expression of CsLHCB genes was tissue-specific, predominantly in leaves. CsLHCB5 may play a key role in the process of leaf maturation and senescence. In contrast to CsLHCB5, CsLHCB1.1, CsLHCB2, and CsLHCB3.2 were highly conserved in amino acid sequence between green and albino tea cultivars. In albino tea cultivars, unlike in green cultivars, the expression of CsLHCB1.1, CsLHCB1.2, and CsLHCB2 was down-regulated under low-temperature stress. The accumulation of CsLHCB1 and CsLHCB5 proteins was lower in albino tea cultivars. Greater accumulation of CsLHCB2 protein was detected in RX1 and RX2 compared to other albino cultivars.

CONCLUSIONS

CsLHCB1.1, CsLHCB1.2, and CsLHCB2 played a role in the response to low-temperature stress. The amino acid sequence site mutation of CsLHCB5 would distinguish the green and albino tea cultivars. The less accumulation of CsLHCB1 and CsLHCB5 had a Chl influence on albino leaves. Albino cultivars more sensitive to temperature exhibited lower CsLHCB gene expression. CsLHCB2 may serve as an indicator of temperature sensitivity differences in albino tea cultivars. This study could provide a reference for further studies of the functions of the CsLHCB family and contribute to research on the mechanism of the albino in tea plant.

Multi-locus genome-wide association study for grain yield and drought tolerance indices in sorghum accessions

Drought is a significant factor that causes yield loss in essential cereal crops such as sorghum [Sorghum bicolor (L.) Moench], necessitating the development of drought-tolerant varieties adaptable to various water conditions. This study aimed to pinpoint drought-tolerant sorghum lines and genomic regions for tolerance by utilizing 216 sorghum accessions in stressed and non-stressed environments at two locations. Genetic diversity was evident among accessions in terms of grain yield under different watering regimes. Drought stress indices such as the stress tolerance index, mean productivity, geometric mean productivity, harmonic mean productivity, yield stability index, and yield index were identified as effective measures for selecting drought-tolerant sorghum. Cluster analysis classified genotypes into four groups based on their association with grain yield, highlighting Acc. #28546 and Acc. #216739 as highly drought tolerant across environments. This study identified 32 and 22 quantitative trait nucleotides (QTNs) for drought indices and grain yield under stress and non-stress conditions, respectively, at two locations, with five common QTNs linked to multiple drought indices. Colocation analysis revealed that these QTNs were associated with known stay-green-related quantitative trait loci (QTLs), and 47 putative genes near these QTNs potentially influenced drought tolerance traits. It is suggested that accession selection considers multiple indices for robust evaluation. Understanding the identified genes and their functions provides insights into the genetic mechanisms governing plant responses to drought stress, offering prospects for developing improved drought-resistant sorghum varieties through further genetic research.

Genome-Wide Identification of the Lectin Receptor-like Kinase Gene Family in Avena sativa and Its Role in Salt Stress Tolerance

Lectin receptor-like kinases (LecRLKs) are membrane-bound receptor genes found in many plant species. They are involved in perceiving stresses and responding to the environment. Oat (Avena sativa; 2n = 6x = 42) are an important food and forage crop with potential in drought, saline, or alkaline soils. Here, we present a comprehensive genome-wide analysis of the LecRLK gene family in A. sativa and the crop's wild relatives A. insularis (4x) and A. longiglumis (2x), unveiling a rich diversity with a total of 390 LecRLK genes identified, comprising 219 G-types, 168 L-types, and 3 C-types in oats. Genes were unevenly distributed across the oat chromosomes. GFP constructs show that family members were predominantly located in the plasma membrane. Expression under salt stress demonstrated functional redundancy and differential expression of LecRLK gene family members in oats: 173 members of this family were involved in the response to salt stress, and the expression levels of three C-type genes in the root and leaf were significantly increased under salt stress. The results show the diversity, evolutionary dynamics, and functional implications of the LecRLK gene family in A. sativa, setting a foundation for defining its roles in plant development and stress resilience, and suggesting its potential agricultural application for crop improvement.

Characteristics of Callus and Cell Suspension Cultures of Highbush Blueberry (Vaccinium corymbosum L.) Cultivated in the Presence of Different Concentrations of 2,4-D and BAP in a Nutrient Medium

In this work, cultures of callus and suspension cells originating from leaves of sterile highbush blueberry (Vaccinium corymbosum L.) plants were obtained and characterized. For their active growth and production of phenolic compounds, a combination of 2,4-D at a concentration of 0.34-2.25 µM and BAP at a concentration of 0.45-2.25 µM is effective. An increase in the phytohormone concentration leads to a slowdown in culture formation and reduces their ability to synthesize phenolic compounds. When cultivating V. corymbosum suspension cells over a year (12 passages), they not only retain the ability to synthesize phenolic compounds but also enhance it. By the 12th passage, the content of TSPC in suspension cells reaches 150 mg/g DW, the content of flavonoids reaches 100 mg/g DW, the content of flavans reaches 40 mg/g DW, and the content of proanthocyanidins reaches 30 mg/g DW. The high content of phenolic compounds may be due to the high expression of genes in flavonoid biosynthesis enzymes. V. corymbosum suspension cells accumulate a high level of phenolic compounds during a passage. The ability of V. corymbosum callus and cell suspension cultures in the presence of low concentrations of phytohormones to grow and accumulate biologically active phenolic compounds determines their high economic significance and prospects for organizing a biotechnological method for obtaining phenolic compounds.

Integrated Transcriptome and sRNAome Analysis Reveals the Molecular Mechanisms of Piriformospora indica-Mediated Resistance to Fusarium Wilt in Banana

Bananas (Musa spp.) are among the most important fruit and staple food crops globally, holding a significant strategic position in food security in tropical and subtropical regions. However, the industry is grappling with a significant threat from Fusarium wilt, a disease incited by Fusarium oxysporum f. sp. cubense (Foc). In this study, we explored the potential of Piriformospora indica (Pi), a mycorrhizal fungus renowned for bolstering plant resilience and nutrient assimilation, to fortify bananas against this devastating disease. Through a meticulous comparative analysis of mRNA and miRNA expression in control, Foc-inoculated, Pi-colonized, and Pi-colonized followed by Foc-inoculated plants via transcriptome and sRNAome, we uncovered a significant enrichment of differentially expressed genes (DEGs) and DE miRNAs in pathways associated with plant growth and development, glutathione metabolism, and stress response. Our findings suggest that P. indica plays a pivotal role in bolstering banana resistance to Foc. We propose that P. indica modulates the expression of key genes, such as glutathione S-transferase (GST), and transcription factors (TFs), including TCP, through miRNAs, thus augmenting the plant's defensive capabilities. This study offers novel perspectives on harnessing P. indica for the management of banana wilt disease.

Overexpression of the Kiwifruit Transcription Factor AaMYB44 Decreases the Cold Tolerance in Arabidopsis thaliana

Cold stress is one of the main abiotic stresses that affect the development and growth of kiwifruit (Actinidia arguta). Herein, we analyzed the transcriptomic data of A. arguta dormant shoots in response to low-temperature treatment, identified 52 MYB genes, and constructed a phylogenetic tree based on the encoded protein sequences. Then, the effect of one MYB gene on cold tolerance was analyzed. This gene had an open reading frame of 837 bp long and encoded 279 amino acids. Sequence alignment and phylogenetic analysis revealed that this gene belongs to the R2R3-MYB family and was named AaMYB44 based on its homology to other MYB family members. Quantitative real-time PCR revealed that AaMYB44 expression was significantly induced by low temperatures but exhibited the opposite trend in cold-tolerant genotypes. Subcellular localization assays revealed the nuclear localization of the AaMYB44 protein. Furthermore, AaMYB44 was transformed into Arabidopsis thaliana (A. thaliana) via inflorescence infection, and physiological and biochemical tests revealed that the cold resistance and antioxidant capacity of the transgenic A. thaliana were lower than those of wild-type plants. Overall, AaMYB44 might play a negative regulatory role in response to cold stress, providing new insight into the mechanism of cold tolerance.

The MYC2 and MYB43 transcription factors cooperate to repress HMA2 and HMA4 expression, altering cadmium tolerance in Arabidopsis thaliana

Cadmium (Cd) represents a hazardous heavy metal, prevalent in agricultural soil due to industrial and agricultural expansion. Its propensity for being absorbed by edible plants, even at minimal concentrations, and subsequently transferred along the food chain poses significant risks to human health. Accordingly, it is imperative to investigate novel genes and mechanisms that govern Cd tolerance and detoxification in plants. Here, we discovered that the transcription factor MYC2 directly binds to the promoters of HMA2 and HMA4 to repress their expression, thereby altering the distribution of Cd in plant tissues and negatively regulating Cd stress tolerance. Additionally, molecular, biochemical, and genetic analyses revealed that MYC2 interacts and cooperates with MYB43 to negatively regulate the expression of HMA2 and HMA4 and Cd stress tolerance. Notably, under Cd stress conditions, MYC2 undergoes degradation, thereby alleviating its inhibitory effect on HMA2 and HMA4 expression and plant tolerance to Cd stress. Thus, our study highlights the dynamic regulatory role of MYC2, in concert with MYB43, in regulating the expression of HMA2 and HMA4 under both normal and Cd stress conditions. These findings present MYC2 as a promising target for directed breeding efforts aimed at mitigating Cd accumulation in edible plant roots.

Overexpression of PsMYB62 from Potentilla sericea confers cadmium tolerance in tobacco

Excessive cadmium (Cd) content in soil poses serious hazard to the survival and development of various organisms. Potentilla sericea, characterized by strong resistance and high utility value, is an excellent choice for urban ecological greening. Plant MYB transcription factors can participate in respondind to a variety of abiotic stresses such as heavy metals and salinity. In this study, PsMYB62 was transformed into tobacco by leaf disc infestation to obtain PsMYB62 overexpressing tobacco lines, and its mechanism in response to Cd stress was further investigated. The results showed that with Cd treatment, PsMYB62 overexpressing tobacco exhibited significantly higher net photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO2 concentration, chlorophyll content, as well as enhanced activities of superoxide dismutase, peroxidase, catalase, and glutathione reductase enzymes, along with increased levels of reduced glutathione, proline, and soluble protein compared to the control. Conversely, levels of O2- and H2O2, and malondialdehyde were markedly lower than those in the control(P<0.05). Moreover, the aboveground Cd content was notably higher in the control than in the transgenic lines, whereas the control was much lower than the transgenic lines in the belowground fraction, with Cd subcellular distribution ratios ranking as follows: cell wall fraction > soluble fraction > organelle fraction (P<0.05). The expression of NtHMA3, NtYSL, NtPDR4 and NtPDR5B were much lower in transgenic lines compared to the control, while NtNAS3, NtSOD, and NtGSH2 exhibited significantly higher expression. Consequently, this study provides genetic resources for molecular breeding of Cd-tolerant plants through genetic engineering and lays a theoretical foundation for the remediation of heavy metal-contaminated soil.

Characterization and functions of Myeloblastosis (MYB) transcription factors in cucurbit crops

Myeloblastosis (MYB) is one of the largest family of transcription factors (TFs) in plants. It plays a key role in plant life activities, such as metabolic regulation, stress resistant, as well as helpful for plant growth and development. In China, cucurbit is an important and nutrients rich vegetable crop, which have high medicinal and socio-economic values. In this review, we discussed the structure and characterization of MYB TFs and how do regulate flower development, fruit maturity, fruit quality, and flavonoid biosynthesis. Furthermore, we highlight the effect and contribution of MYB TFs in the regulation of biotic and abiotic stress resistance. This comprehensive review will provide a new reference for the more effective application of MYB TF in quality control, stress resistance research and molecular breeding of cucurbit crops.

A R2R3-MYB transcription factor, FeR2R3-MYB, positively regulates anthocyanin biosynthesis and drought tolerance in common buckwheat (Fagopyrum esculentum)

The R2R3-MYB transcription factors (TFs) play a crucial role in regulating plant secondary metabolism and abiotic stress responses, yet they are still poorly understood in common buckwheat (Fagopyrum esculentum), a valuable minor grain crop resource. In this study, a candidate gene, FeR2R3-MYB, was cloned from the anthocyanin-rich common buckwheat variety 'QZZTQ'. FeR2R3-MYB was found to contain two MYB DNA-binding domains and be located at the nucleus with transcriptional activation activity. Molecular analysis indicated that FeR2R3-MYB is predominantly expressed in flowering tissue and is highly responsive to environmental factors such as light, drought, and cold. In addition, the promoter of FeR2R3-MYB showed a positive correlation with fragment length. Further functional analysis suggested that FeR2R3-MYB not only participates in the anthocyanin biosynthetic pathway by interacting with leucoanthocyanidin reductase (FeLAR), but also enhances drought tolerance in common buckwheat. To sum up, FeR2R3-MYB exhibits positive effects on both pigment production (e.g., anthocyanin) and abiotic stress resistance, providing valuable insights for future research in buckwheat molecular breeding and resource development.

Cullin-Conciliated Regulation of Plant Immune Responses: Implications for Sustainable Crop Protection

Cullins are crucial components of the ubiquitin-proteasome system, playing pivotal roles in the regulation of protein metabolism. This review provides insight into the wide-ranging functions of cullins, particularly focusing on their impact on plant growth, development, and environmental stress responses. By modulating cullin-mediated protein mechanisms, researchers can fine-tune hormone-signaling networks to improve various agronomic traits, including plant architecture, flowering time, fruit development, and nutrient uptake. Furthermore, the targeted manipulation of cullins that are involved in hormone-signaling pathways, e.g., cytokinin, auxin, gibberellin, abscisic acids, and ethylene, can boost crop growth and development while increasing yield and enhancing stress tolerance. Furthermore, cullins also play important roles in plant defense mechanisms through regulating the defense-associated protein metabolism, thus boosting resistance to pathogens and pests. Additionally, this review highlights the potential of integrating cullin-based strategies with advanced biological tools, such as CRISPR/Cas9-mediated genome editing, genetic engineering, marker-associated selections, gene overexpression, and gene knockout, to achieve precise modifications for crop improvement and sustainable agriculture, with the promise of creating resilient, high-yielding, and environmentally friendly crop varieties.

Identifying a cis-element in PtoCP1 promoter for efficiently controlling constitutive gene expression in Populus tomentosa

Gene expression is regulated by transcription factors binding to cis-elements in promoters. However, efficient cis-elements for genetic engineering are rarely reported. In this study, we identified an 11 bp cis-element in the PtoCP1 promoter that drives strong constitutive gene expression in Populus tomentosa. A 2,270 bp promoter region upstream of the PtoCP1 gene's translation start site was cloned and named ProPtoCP1. This promoter controls GUS reporter gene expression in the roots, leaves, and stems of Arabidopsis seedlings. Based on the location and density of cis-elements, the PtoCP1 promoter was divided into four fragments by 5'-end deletions. GUS staining and RT-qPCR revealed a key cis-element at -466 to -441 bp essential for gene expression. Further analysis showed that the MYB-TGACG cis-element is a positive regulator, whereas neither MYB nor TGACG alone drove gene expression. This study enhances our understanding of gene expression regulation by cis-elements and provides a valuable tool for genetic engineering.

Genome-Wide Identification of the Cyclic Nucleotide-Gated Ion Channel Gene Family and Expression Profiles Under Low-Temperature Stress in Luffa cylindrica L

Cyclic nucleotide-gated ion channels (CNGCs) are cell membrane channel proteins for calcium ions. They have been reported to play important roles in survival and in the responses to environmental factors in various plants. However, little is known about the CNGC family and its functions in luffa (Luffa cylindrica L.). In this study, a bioinformatics-based method was used to identify members of the CNGC gene family in L. cylindrica. In total, 20 LcCNGCs were detected, and they were grouped into five subfamilies (I, II, Ⅲ, IV-a, and IV-b) in a phylogenetic analysis with CNGCs from Arabidopsis thaliana (20 AtCNGCs) and Momordica charantia (17 McCNGCs). The 20 LcCNGC genes were unevenly distributed on 11 of the 13 chromosomes in luffa, with none on Chromosomes 1 and 5. The members of each subfamily encoded proteins with highly conserved functional domains. An evolutionary analysis of CNGCs in luffa revealed three gene losses and a motif deletion. An examination of gene replication events during evolution indicated that two tandemly duplicated gene pairs were the primary driving force behind the evolution of the LcCNGC gene family. PlantCARE analyses of the LcCNGC promoter regions revealed various cis-regulatory elements, including those responsive to plant hormones (abscisic acid, methyl jasmonate, and salicylic acid) and abiotic stresses (light, drought, and low temperature). The presence of these cis-acting elements suggested that the encoded CNGC proteins may be involved in stress responses, as well as growth and development. Transcriptome sequencing (RNA-seq) analyses revealed tissue-specific expression patterns of LcCNGCs in various plant parts (roots, stems, leaves, flowers, and fruit) and the upregulation of some LcCNGCs under low-temperature stress. To confirm the accuracy of the RNA-seq data, 10 cold-responsive LcCNGC genes were selected for verification by quantitative real-time polymerase chain reaction (RT-qPCR) analysis. Under cold conditions, LcCNGC4 was highly upregulated (>50-fold increase in its transcript levels), and LcCNGC3, LcCNGC6, and LcCNGC13 were upregulated approximately 10-fold. Our findings provide new information about the evolution of the CNGC family in L. cylindrica and provide insights into the functions of the encoded CNGC proteins.

Genome-wide identification and analysis of anthocyanin synthesis-related R2R3-MYB genes in Fragaria pentaphylla

BACKGROUND

MYB transcription factors regulate anthocyanin biosynthesis across numerous plant species. However, comprehensive genome-wide investigations regarding the R2R3-MYB gene family and its involvement in regulating anthocyanin biosynthesis in the red and white fruit color morphs of Fragaria pentaphylla remain scarce.

RESULTS

A total of 101 FpR2R3-MYB genes were identified from the F. pentaphylla genome and were divided into 34 subgroups based on phylogenetic analysis. Gene structure (exon/intron) and protein motifs were particularly conserved among the FpR2R3-MYB genes, especially members within the same subgroup. The FpR2R3-MYB genes were distributed over seven F. pentaphylla chromosomes. Analysis of gene duplication events revealed five pairs of tandem duplication genes and 16 pairs of segmental duplication genes, suggesting that segmental duplications are the major pattern for expansion of the FpR2R3-MYB gene family expansion in F. pentaphylla. Cis-regulatory elements of the FpR2R3-MYB promoters were involved in cellular development, phytohormones, environmental stress and photoresponse. Based on the analysis of the FpR2R3-MYB gene family and transcriptome sequencing (RNA-seq) data, FpMYB9 was identified as a key transcription factor involved in the regulation of anthocyanin synthesis in F. pentaphylla fruits. The expression of FpMYB9 increases significantly during the ripening stage of red fruits, as confirmed by reverse transcription quantitative real-time PCR. In addition, subcellular localization experiments further confirmed the nuclear presence of FpMYB9, supporting its role as a transcription factor involved in anthocyanin biosynthesis.

CONCLUSION

Our results showed that the FpR2R3-MYB genes are highly conserved and play important roles in the anthocyanin biosynthesis in F. pentaphylla fruits. Our results also provide a compelling basis for further understanding of the regulatory mechanism underlying the role of FpMYB9 in anthocyanin formation in F. pentaphylla fruits.

Nuclear integration of MYB36 and APX-1 genes impart heat tolerance in wheat

Elevated temperatures during grain filling stage, exceeding the optimal range by 3-4 °C, not only results in a substantial yield reduction in wheat by 10-50% but activates disease and insect infestation. In this research, we introduced heat-tolerant MYB36 and APX-1 gene cassettes into wheat, employing an efficient Agrobacterium mediated transformation protocol, demonstrating higher transformation efficiency. The study encompassed the assembly of MYB36 and APX-1 gene cassettes, and confirmation of gene products in Agrobacterium, followed by the transformation of the MYB36 and APX-1 genes into wheat explants. We were able to select transgenic plant with various combinations. The transgenic plants with APX-1 gene alone produced medium sized grain and spike whereas with both APX-1 and MYB36 genes expressed individually under SPS and rd29a promoter respectively showed good tolerance to heat at 32oC at grain filling/milking stage and produced relatively bold grains. While non-transgenic plants grains were wrinkled with thin spike showing susceptibility to heat. This research contributes to the broader scientific understanding of plant stress responses and the combined effectiveness of MYB36 and APX-1 genes in crop improvement without disturbing normal nutritional values. The gene integration can serve as a valuable tool in breeding programs aimed at developing heat-tolerant wheat varieties. These findings also advance our comprehension of the functions of heat-induced genes and lay the foundation for selecting optimal candidates for in-depth functional studies of heat-responsive MYB36 and APX-1 genes in wheat.