Slight drought during flowering period can improve Tartary buckwheat yield by regulating carbon and nitrogen metabolism

This study aimed to clarify the effects of drought during flowering period on the carbon and nitrogen metabolism, growth, and yield of Tartary buckwheat. Tartary buckwheat cultivar Jinqiao 2 was treated with well-watered (CK), slight soil-drought stress (LD), moderate soil-drought stress (MD), and severe soil-drought stress (SD), with the soil water potential maintained at - 0.02 to - 0.03, - 0.04 to - 0.05, - 0.05 to - 0.06, and - 0.06 to - 0.07 MPa, respectively. With prolonged growth period and an increase in drought stress, the antioxidant enzyme activities and the contents of substances and activities of enzymes related to carbon and nitrogen metabolism in Tartary buckwheat leaves initially increased and then decreased. Meanwhile, the contents of malondialdehyde and superoxide anion showed a continuous. LD treatment induced the highest antioxidant enzyme activities and the contents of substances and activities of enzymes related to carbon and nitrogen metabolism but the lowest contents of malondialdehyde and superoxide anion in Tartary buckwheat leaves. Compared with CK, LD treatment increased the grain number, 1000-grain weight (MTS), and yield per plant by 6.52%, 17.37%, and 12.35%, respectively. In summary, LD treatment can increase the antioxidant enzyme activities and the contents of substances and activities of enzymes related to carbon and nitrogen metabolism, thus enhancing the adaptability of Tartary buckwheat to drought stress and increasing the yield per plant.

Effects of trimer repeats on Psidium guajava L. gene expression and prospection of functional microsatellite markers

Most research on trinucleotide repeats (TRs) focuses on human diseases, with few on the impact of TR expansions on plant gene expression. This work investigates TRs' effect on global gene expression in Psidium guajava L., a plant species with widespread distribution and significant relevance in the food, pharmacology, and economics sectors. We analyzed TR-containing coding sequences in 1,107 transcripts from 2,256 genes across root, shoot, young leaf, old leaf, and flower bud tissues of the Brazilian guava cultivars Cortibel RM and Paluma. Structural analysis revealed TR sequences with small repeat numbers (5-9) starting with cytosine or guanine or containing these bases. Functional annotation indicated TR-containing genes' involvement in cellular structures and processes (especially cell membranes and signal recognition), stress response, and resistance. Gene expression analysis showed significant variation, with a subset of highly expressed genes in both cultivars. Differential expression highlighted numerous down-regulated genes in Cortibel RM tissues, but not in Paluma, suggesting interplay between tissues and cultivars. Among 72 differentially expressed genes with TRs, 24 form miRNAs, 13 encode transcription factors, and 11 are associated with transposable elements. In addition, a set of 20 SSR-annotated, transcribed, and differentially expressed genes with TRs was selected as phenotypic markers for Psidium guajava and, potentially for closely related species as well.

Laser capture microdissection transcriptome (LCM RNA-seq) reveals BcDFR is a key gene in anthocyanin synthesis of non-heading Chinese cabbage

BACKGROUND

Purple non-heading Chinese cabbage [Brassica campestris (syn. Brassica rapa) ssp. chinensis] has become popular because of its richness in anthocyanin. However, anthocyanin only accumulates in the upper epidermis of leaves. Further studies are needed to investigate the molecular mechanisms underlying the specific accumulation of it.

RESULTS

In this study, we used the laser capture frozen section method (LCM) to divide purple (ZBC) and green (LBC) non-heading Chinese cabbage leaves into upper and lower epidermis parts (Pup represents the purple upper epidermis, Plow represents the purple lower epidermis, Gup represents the green upper epidermis, Glow represents the green lower epidermis). Through transcriptome sequencing, we found that the DIHYDROFLAVONOL 4-REDUCTASE-encoding gene BcDFR, is strongly expressed in Pup but hardly in others (Plow, Gup, Glow). Further, a deletion and insertion in the promoter of BcDFR in LBC were found, which may interfere with BcDFR expression. Subsequent analysis of gene structure and conserved structural domains showed that BcDFR is highly conserved in Brassica species. The predicted protein-protein interaction network of BcDFR suggests that it interacts with almost all functional proteins in the anthocyanin biosynthesis pathway. Finally, the results of the tobacco transient expression also demonstrated that BcDFR promotes the synthesis and accumulation of anthocyanin.

CONCLUSIONS

BcDFR is specifically highly expressed on the upper epidermis of purple non-heading Chinese cabbage leaves and regulates anthocyanin biosynthesis and accumulation. Our study provides new insights into the functional analysis and transcriptional regulatory network of anthocyanin-related genes in purple non-heading Chinese cabbage.

Transcriptome differential expression analysis of defoliation of two different lemon varieties

'Allen Eureka' is a bud variety of Eureka lemon with excellent fruiting traits. However, it suffers from severe winter defoliation that leads to a large loss of organic nutrients and seriously affects the tree's growth and development as well as the yield of the following year, and the mechanism of its response to defoliation is still unclear. In order to investigate the molecular regulatory mechanisms of different leaf abscission periods in lemon, two lemon cultivars ('Allen Eureka' and 'Yunning No. 1') with different defoliation traits were used as materials. The petiole abscission zone (AZ) was collected at three different defoliation stages, namely, the pre-defoliation stage (CQ), the mid-defoliation stage (CZ), and the post-defoliation stage (CH). Transcriptome sequencing was performed to analyze the gene expression differences between these two cultivars. A total of 898, 4,856, and 3,126 differentially expressed genes (DEGs) were obtained in CQ, CZ, and CH, respectively, and the number of DEGs in CZ was the largest. GO analysis revealed that the DEGs between the two cultivars were mainly enriched in processes related to oxidoreductase, hydrolase, DNA binding transcription factor, and transcription regulator activity in the defoliation stages. KEGG analysis showed that the DEGs were concentrated in CZ and involved plant hormone signal transduction, phenylpropanoid biosynthesis, glutathione metabolism, and alpha-linolenic acid metabolism. The expression trends of some DEGs suggested their roles in regulating defoliation in lemon. Eight gene families were obtained by combining DEG clustering analysis and weighted gene co-expression network analysis (WGCNA), including β-glucosidase, AUX/IAA, SAUR, GH3, POD, and WRKY, suggesting that these genes may be involved in the regulation of lemon leaf abscission. The above conclusions enrich the research related to lemon leaf abscission and provide reliable data for the screening of lemon defoliation candidate genes and analysis of defoliation pathways.

Gene expression analysis of drought tolerance and cuticular wax biosynthesis in diploid and tetraploid induced wallflowers

Whole-genome doubling leads to cell reprogramming, upregulation of stress genes, and establishment of new pathways of drought stress responses in plants. This study investigated the molecular mechanisms of drought tolerance and cuticular wax characteristics in diploid and tetraploid-induced Erysimum cheiri. According to real-time PCR analysis, tetraploid induced wallflowers exhibited increased expression of several genes encoding transcription factors (TFs), including AREB1 and AREB3; the stress response genes RD29A and ERD1 under drought stress conditions. Furthermore, two cuticular wax biosynthetic pathway genes, CER1 and SHN1, were upregulated in tetraploid plants under drought conditions. Leaf morphological studies revealed that tetraploid leaves were covered with unique cuticular wax crystalloids, which produced a white fluffy appearance, while the diploid leaves were green and smooth. The greater content of epicuticular wax in tetraploid leaves than in diploid leaves can explain the decrease in cuticle permeability as well as the decrease in water loss and improvement in drought tolerance in wallflowers. GC‒MS analysis revealed that the wax components included alkanes, alcohols, aldehydes, and fatty acids. The most abundant wax compound in this plant was alkanes (50%), the most predominant of which was C29. The relative abundance of these compounds increased significantly in tetraploid plants under drought stress conditions. These findings revealed that tetraploid-induced wallflowers presented upregulation of multiple drought-related and wax biosynthesis genes; therefore, polyploidization has proved useful for improving plant drought tolerance.

[Uncovering the molecular mechanisms behind steroidal saponin accumulation in Liriope muscari (Decne.) Baily through transcriptome sequencing and bioinformatics analysis]

The leaves and roots of Liriope muscari (Decne.) Baily were subjected to high-throughput Illumina transcriptome sequencing. Bioinformatics analysis was used to investigate the enzyme genes and key transcription factors involved in regulating the accumulation of steroidal saponins, which are the main active ingredient in L. muscari. These analyses aimed to reveal the molecular mechanism behind steroidal saponin accumulation. The sequencing results of L. muscari revealed 31 enzymes, including AACT, CAS, DXS and DXR, that are involved in the synthesis of steroidal saponins. Among these enzymes, 16 were in the synthesis of terpenoid skeleton, 3 were involved in the synthesis of sesquiterpene and triterpene, and 12 were involved in the synthesis of steroidal compound. Differential gene expression identified 15 metabolic enzymes coded by 34 differentially expressed genes (DEGs) in the leaves and roots, which were associated with steroidal saponin synthesis. Further analysis using gene co-expression patterns showed that 14 metabolic enzymes coded by 31 DEGs were co-expressed. In addition, analysis using gene co-expression analysis and PlantTFDB's transcription factor analysis tool predicted the involvement of 8 transcription factors, including GAI, PIF4, PIL6, ERF8, SVP, LHCA4, NF-YB3 and DOF2.4, in regulating 6 metabolic enzymes such as DXS, DXR, HMGR, DHCR7, DHCR24, and CAS. These eight transcription factors were predicted to play important roles in regulating steroidal saponin accumulation in L. muscari. Promoter analysis of these transcription factors indicated that their main regulatory mechanisms involve processes such as abscisic acid response, drought-induction stress response and light response, especially abscisic acid responsive elements (ABRE) response and MYB binding site involved in drought-inducibility (MBS) response pathway. Furthermore, qRT-PCR analysis of these eight key transcription factors demonstrated their specific differences in the leaves and roots.

Phytosynthesis of silver nanoparticles using aqueous sandalwood (Santalum album L.) leaf extract: Divergent effects of SW-AgNPs on proliferating plant and cancer cells

The biogenic approach for the synthesis of metal nanoparticles provides an efficient eco-friendly alternative to chemical synthesis. This study presents a novel route for the biosynthesis of silver nanoparticles using aqueous sandalwood (SW) leaf extract as a source of reducing and capping agents under mild, room temperature synthesis conditions. The bioreduction of Ag+ to Ago nanoparticles (SW-AgNPs) was accompanied by the appearance of brown color, with surface plasmon resonance peak at 340-360 nm. SEM, TEM and AFM imaging confirm SW-AgNP's spherical shape with size range of 10-32 nm. DLS indicates a hydrodynamic size of 49.53 nm with predominant negative Zeta potential, which can contribute to the stability of the nanoparticles. FTIR analysis indicates involvement of sandalwood leaf derived polyphenols, proteins and lipids in the reduction and capping of SW-AgNPs. XRD determines the face-centered-cubic crystalline structure of SW-AgNPs, which is a key factor affecting biological functions of nanoparticles. This study is novel in using cell culture methodologies to evaluate effects of SW-AgNPs on proliferating cells originating from plants and human cancer. Exposure of groundnut calli cells to SW-AgNPs, resulted in enhanced proliferation leading to over 70% higher calli biomass over control, enhanced defense enzyme activities, and secretion of metabolites implicated in biotic stress resistance (Crotonyl isothiocyanate, Butyrolactone, 2-Hydroxy-gamma-butyrolactone, Maltol) and plant cell proliferation (dl-Threitol). MTT and NRU were performed to determine the cytotoxicity of nanoparticles on human cervical cancer cells. SW-AgNPs specifically inhibited cervical cell lines SiHa (IC50-2.65 ppm) and CaSki (IC50-9.49 ppm), indicating potential use in cancer treatment. The opposing effect of SW-AgNPs on cell proliferation of plant calli (enhanced cell proliferation) and human cancer cell lines (inhibition) are both beneficial and point to potential safe application of SW-AgNPs in plant cell culture, agriculture and in cancer treatment.

Antibiotics Uptake from Soil and Translocation in the Plants - Meta-analysis

Antibiotics reach agricultural soils via fertilization with manure and biosolids as well as irrigation withwastewater and have the potential to be taken up by growing crops. The fate of antibiotics in terms of uptakefrom soil to plants, as well as translocation from root to leaves, is determined by a combination of antibiotic'sphysio-chemical (e.g. speciation, lipophilicity), soil (e.g. organic carbon content, pH) and plant (e.g.transpiration rates) characteristics. In this meta-analysis, a literature search was executed to obtain an overview of antibiotic uptake to plants, with an aim to identify uptake and translocation patterns of different antibiotic classes. Overall, we found that higher uptake of tetracyclines to plant leaves was observed compared to sulfonamides. Differences were also observed in translocation within the plants, where tetracyclines were found in roots and leaves with close to equal concentrations, while the sulfonamides represented a tendency to accumulate to the root fraction. The antibiotic's characteristics have a high influence on their fate, for example, the high water-solubility and uncharged speciation in typical agricultural soil pH ranges likely induces tetracycline uptake from soil and translocation in plant. Despite the advances in knowledge over the past decade, our meta-analysis indicated that the available research is focused on a limited number of analytes and antibiotic classes. Furthermore, fastgrowing plant species (e.g. spinach, lettuce, and radish) are overly represented in studies compared to crop species with higher significance for human food sources (e.g. corn, wheat, and potato), requiring more attention in future research.

Control of leaf development in the water fern Ceratopteris richardii by the auxin efflux transporter CrPINMa in the CRISPR/Cas9 analysis

BACKGROUND

PIN-FORMED genes (PINs) are crucial in plant development as they determine the directionality of auxin flow. They are present in almost all land plants and even in green algae. However, their role in fern development has not yet been determined. This study aims to investigate the function of CrPINMa in the quasi-model water fern Ceratopteris richardii.

RESULTS

CrPINMa possessed a long central hydrophilic loop and characteristic motifs within it, which indicated that it belonged to the canonical rather than the non-canonical PINs. CrPINMa was positioned in the lineage leading to Arabidopsis PIN6 but not that to its PIN1, and it had undergone numerous gene duplications. CRISPR/Cas9 genome editing had been performed in ferns for the first time, producing diverse mutations including local frameshifts for CrPINMa. Plants possessing disrupted CrPINMa exhibited retarded leaf emergence and reduced leaf size though they could survive and reproduce at the same time. CrPINMa transcripts were distributed in the shoot apical meristem, leaf primordia and their vasculature. Finally, CrPINMa proteins were localized to the plasma membrane rather than other cell parts.

CONCLUSIONS

CRISPR/Cas9 genome editing is feasible in ferns, and that PINs can play a role in fern leaf development.

Histochemical, metabolic and ultrastructural changes in leaf patelliform nectaries explain extrafloral nectar synthesis and secretion in Clerodendrum chinense

BACKGROUND AND AIMS

Extrafloral nectaries are nectar-secreting structures present on vegetative parts of plants which provide indirect defences against herbivore attack. Extrafloral nectaries in Clerodendrum chinense are patelliform-shaped specialized trichomatous structures. However, a complete understanding of patelliform extrafloral nectaries in general, and of C. chinense in particular, has not yet been established to provide fundamental insight into the cellular physiological machinery involved in nectar biosynthesis and secretory processes.

METHODS

We studied temporal changes in the morphological, anatomical and ultrastructural features in the architectures of extrafloral nectaries. We also compared metabolite profiles of extrafloral nectar, nectary tissue, non-nectary tissue and phloem sap. Further, both in situ histolocalization and normal in vitro activities of enzymes related to sugar metabolism were examined.

KEY RESULTS

Four distinct tissue regions in the nectar gland were revealed from histochemical characterization, among which the middle nectariferous tissue was found to be the metabolically active region, while the intermediate layer was found to be lipid-rich. Ultrastructural study showed the presence of a large number of mitochondria along with starch-bearing chloroplasts in the nectariferous region. However, starch depletion was noted with progressive maturation of nectaries. Metabolite analysis revealed compositional differences among nectar, phloem sap, nectary and non-nectary tissue. Invertase activity was higher in secretory stages and localized in nectariferous tissue and adjacent region.

CONCLUSIONS

Our study suggests extrafloral nectar secretion in C. chinense to be both eccrine and merocrine in nature. A distinct intermediate lipid-rich layer that separates the epidermis from nectary parenchyma was revealed, which possibly acts as a barrier to water flow in nectar. This study also revealed a distinction between nectar and phloem sap, and starch could act as a nectar precursor, as evidenced from enzymatic and ultrastructural studies. Thus, our findings on changing architecture of extrafloral nectaries with temporal secretion revealed a cell physiological process involved in nectar biosynthesis and secretion.

Carbon Nanomaterials for Plant Priming through Mechanostimulation: Emphasizing the Role of Shape

The use of nanomaterials to improve plant immunity for sustainable agriculture is gaining increasing attention; yet, the mechanisms involved remain unclear. In contrast to metal-based counterparts, carbon-based nanomaterials do not release components. Determining how these carbon-based nanomaterials strengthen the resistance of plants to diseases is essential as well as whether shape influences this process. Our study compared single-walled carbon nanotubes (SWNTs) and graphene oxide (GO) infiltration against the phytopathogen Pseudomonas syringae pv tomato DC3000. Compared with plants treated with GO, plants primed with SWNTs showed a 29% improvement in the pathogen resistance. Upon nanopriming, the plant displayed wound signaling with transcriptional regulation similar to that observed under brushing-induced mechanostimulation. Compared with GO, SWNTs penetrated more greatly into the leaf and improved transport, resulting in a heightened wound response; this effect resulted from the tubular structure of SWNTs, which differed from the planar form of GO. The shape effect was further demonstrated by wrapping SWNTs with bovine serum albumin, which masked the sharp edges of SWNTs and resulted in a significant decrease in the overall plant wound response. Finally, we clarified how the local wound response led to systemic immunity through increased calcium ion signaling in distant plant areas, which increased the antimicrobial efficacy. In summary, our systematic investigation established connections among carbon nanomaterial priming, mechanostimulation, and wound response, revealing recognition patterns in plant immunity. These findings promise to advance nanotechnology in sustainable agriculture by strengthening plant defenses, enhancing resilience, and reducing reliance on traditional chemicals.

CsREV-CsTCP4-CsVND7 module shapes xylem patterns differentially between stem and leaf to enhance tea plant tolerance to drought

Cultivating drought-tolerant tea varieties enhances both yield and quality of tea plants in northern China. However, the mechanisms underlying their drought tolerance remain largely unknown. Here we identified a key regulator called CsREV, which differentially regulates xylem patterns between leaves and stems, thereby conferring drought tolerance in tea plants. When drought occurs, upregulation of CsREV activates the CsVND7a-dependent xylem vessel differentiation. However, when drought persists, the vessel differentiation is hindered as CsVND7a is downregulated by CsTCP4a. This, combined with the CsREV-promoted secondary-cell-wall thickness of xylem vessel, leads to the enhanced curling of leaves, a characteristic closely associated with plant drought tolerance. Notably, this inhibitory effect of CsTCP4a on CsVND7a expression is absent in stems, allowing stem xylem vessels to continuously differentiate. Overall, the CsREV-CsTCP4-CsVND7 module is differentially utilized to shape the xylem patterns in leaves and stems, potentially balancing water transportation and utilization to improve tea plant drought tolerance.

Three new discovery effector proteins from Candidatus Liberibacter asiaticus psy62 inhibit plant defense through interaction with AtCAT3 and AtGAPA

KEY MESSAGE

We identify three SDEs that inhibiting host defence from Candidatus Liberibacter asiaticus psy62, which is an important supplement to the pathogenesis of HLB. Candidatus Liberibacter asiaticus (CLas) is the main pathogen of citrus Huanglongbing (HLB). 38 new possible sec-dependent effectors (SDEs) of CLas psy62 were predicted by updated predictor SignalP 5.0, which 12 new SDEs were found using alkaline phosphate assay. Among them, SDE4310, SDE4435 and SDE4955 inhibited hypersensitivity reactions (HR) in Arabidopsis thaliana (Arabidopsis, At) and Nicotiana benthamiana leaves induced by pathogens, which lead to a decrease in cell death and reactive oxygen species (ROS) accumulation. And the expression levels of SDE4310, SDE4435, and SDE4955 genes elevated significantly in mild symptom citrus leaves. When SDE4310, SDE4435 and SDE4955 were overexpressed in Arabidopsis, HR pathway key genes pathogenesis-related 2 (PR2), PR5, nonexpressor of pathogenesis-related 1 (NPR1) and isochorismate synthase 1 (ICS1) expression significantly decreased and the growth of pathogen was greatly increased relative to control with Pst DC3000/AvrRps4 treatment. Our findings also indicated that SDE4310, SDE4435 and SDE4955 interacted with AtCAT3 (catalase 3) and AtGAPA (glyceraldehyde-3-phosphate dehydrogenase A). In conclusion, our results suggest that SDE4310, SDE4435 and SDE4955 are CLas psy62 effector proteins that may have redundant functions. They inhibit ROS burst and cell death by interacting with AtCAT3 and AtGAPA to negatively regulate host defense.

Transcriptomic and metabolomic profiling provide insight into the role of sugars and hormones in leaf senescence of Pinellia ternata

KEY MESSAGE

The interaction network and pathway map uncover the potential crosstalk between sugar and hormone metabolisms as a possible reason for leaf senescence in P. ternata. Pinellia ternata, an environmentally sensitive medicinal plant, undergoes leaf senescence twice a year, affecting its development and yield. Understanding the potential mechanism that delays leaf senescence could theoretically decrease yield losses. In this study, a typical senescent population model was constructed, and an integrated analysis of transcriptomic and metabolomic profiles of P. ternata was conducted using two early leaf senescence populations and two stay-green populations. The result showed that two key gene modules were associated with leaf senescence which were mainly enriched in sugar and hormone signaling pathways, respectively. A network constructed by unigenes and metabolisms related to the obtained two pathways revealed that several compounds such as D-arabitol and 2MeScZR have a higher significance ranking. In addition, a total of 130 hub genes in this network were categorized into 3 classes based on connectivity. Among them, 34 hub genes were further analyzed through a pathway map, the potential crosstalk between sugar and hormone metabolisms might be an underlying reason of leaf senescence in P. ternata. These findings address the knowledge gap regarding leaf senescence in P. ternata, providing candidate germplasms for molecular breeding and laying theoretical basis for the realization of finely regulated cultivation in future.

The WIP6 transcription factor TOO MANY LATERALS specifies vein type in C4 and C3 grass leaves

Grass leaves are invariantly strap shaped with an elongated distal blade and a proximal sheath that wraps around the stem. Underpinning this shape is a scaffold of leaf veins, most of which extend in parallel along the proximo-distal leaf axis. Differences between species are apparent both in the vein types that develop and in the distance between veins across the medio-lateral leaf axis. A prominent engineering goal is to increase vein density in leaves of C3 photosynthesizing species to facilitate the introduction of the more efficient C4 pathway. Here, we discover that the WIP6 transcription factor TOO MANY LATERALS (TML) specifies vein rank in both maize (C4) and rice (C3). Loss-of-function tml mutations cause large lateral veins to develop in positions normally occupied by smaller intermediate veins, and TML transcript localization in wild-type leaves is consistent with a role in suppressing lateral vein development in procambial cells that form intermediate veins. Attempts to manipulate TML function in rice were unsuccessful because transgene expression was silenced, suggesting that precise TML expression is essential for shoot viability. This finding may reflect the need to prevent the inappropriate activation of downstream targets or, given that transcriptome analysis revealed altered cytokinin and auxin signaling profiles in maize tml mutants, the need to prevent local or general hormonal imbalances. Importantly, rice tml mutants display an increased occupancy of veins in the leaf, providing a step toward an anatomical chassis for C4 engineering. Collectively, a conserved mechanism of vein rank specification in grass leaves has been revealed.

Exogenous Hemin enhances the antioxidant defense system of rice by regulating the AsA-GSH cycle under NaCl stress

Abiotic stress caused by soil salinization remains a major global challenge that threatens and severely impacts crop growth, causing yield reduction worldwide. In this study, we aim to investigate the damage of salt stress on the leaf physiology of two varieties of rice (Huanghuazhan, HHZ, and Xiangliangyou900, XLY900) and the regulatory mechanism of Hemin to maintain seedling growth under the imposed stress. Rice leaves were sprayed with 5.0 μmol·L-1 Hemin or 25.0 μmol·L-1 ZnPP (Zinc protoporphyrin IX) at the three leaf and one heart stage, followed by an imposed salt stress treatment regime (50.0 mmol·L-1 sodium chloride (NaCl)). The findings revealed that NaCl stress increased antioxidant enzymes activities and decreased the content of nonenzymatic antioxidants such as ascorbate (AsA) and glutathione (GSH). Furthermore, the content of osmoregulatory substances like soluble proteins and proline was raised. Moreover, salt stress increased reactive oxygen species (ROS) content in the leaves of the two varieties. However, spraying with Hemin increased the activities of antioxidants such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and accelerated AsA-GSH cycling to remove excess ROS. In summary, Hemin reduced the effect of salt stress on the physiological characteristics of rice leaves due to improved antioxidant defense mechanisms that impeded lipid peroxidation. Thus, Hemin was demonstrated to lessen the damage caused by salt stress.

The Function of Florigen in the Vegetative-to-Reproductive Phase Transition in and around the Shoot Apical Meristem

Plants undergo a series of developmental phases throughout their life-cycle, each characterized by specific processes. Three critical features distinguish these phases: the arrangement of primordia (phyllotaxis), the timing of their differentiation (plastochron) and the characteristics of the lateral organs and axillary meristems. Identifying the unique molecular features of each phase, determining the molecular triggers that cause transitions and understanding the molecular mechanisms underlying these transitions are keys to gleaning a complete understanding of plant development. During the vegetative phase, the shoot apical meristem (SAM) facilitates continuous leaf and stem formation, with leaf development as the hallmark. The transition to the reproductive phase induces significant changes in these processes, driven mainly by the protein FT (FLOWERING LOCUS T) in Arabidopsis and proteins encoded by FT orthologs, which are specified as 'florigen'. These proteins are synthesized in leaves and transported to the SAM, and act as the primary flowering signal, although its impact varies among species. Within the SAM, florigen integrates with other signals, culminating in developmental changes. This review explores the central question of how florigen induces developmental phase transition in the SAM. Future research may combine phase transition studies, potentially revealing the florigen-induced developmental phase transition in the SAM.

Transcription factors NtNAC028 and NtNAC080 form heterodimers to regulate jasmonic acid biosynthesis during leaf senescence in Nicotiana tabacum

Plant senescence, as a highly integrated developmental stage, involves functional degeneration and nutrient redistribution. NAM/ATAF1/CUC (NAC) transcription factors orchestrate various senescence-related signals and mediate the fine-tuning underlying plant senescence. Previous data revealed that knockout of either NtNAC028 or NtNAC080 leads to delayed leaf senescence in tobacco (Nicotiana tabacum), which implies that NtNAC028 and NtNAC080 play respective roles in the regulation of leaf senescence, although they share 91.87% identity with each other. However, the mechanism underlying NtNAC028- and NtNAC080-regulated leaf senescence remains obscure. Here, we determined that NtNAC028 and NtNAC080 activate a putative jasmonic acid (JA) biosynthetic gene, NtLOX3, and enhance the JA level in vivo. We found that NtNAC028 and NtNAC080 interact with each other and themselves through their NA-terminal region. Remarkably, only the dimerization between NtNAC028 and NtNAC080 stimulated the transcriptional activation activity, but not the DNA binding activity of this heterodimer on NtLOX3. Metabolome analysis indicated that overexpression of either NtNAC028 or NtNAC080 augments both biosynthesis and degradation of nicotine in the senescent stages. Thus, we conclude that NtNAC028 cooperates with NtNAC080 and forms a heterodimer to enhance NtLOX3 expression and JA biosynthesis to trigger the onset of leaf senescence and impact secondary metabolism in tobacco.

Molecular Mechanism of Resistance to Alternaria alternata Apple Pathotype in Apple by Alternative Splicing of Transcription Factor MdMYB6-like

As a fruit tree with great economic value, apple is widely cultivated in China. However, apple leaf spot disease causes significant damage to apple quality and economic value. In our study, we found that MdMYB6-like is a transcription factor without auto-activation activity and with three alternative spliced variants. Among them, MdMYB6-like-β responded positively to the pathogen infection. Overexpression of MdMYB6-like-β increased the lignin content of leaves and improved the pathogenic resistance of apple flesh callus. In addition, all three alternative spliced variants of MdMYB6-like could bind to the promoter of MdBGLU H. Therefore, we believe that MdMYB6-like plays an important role in the infection process of the pathogen and lays a solid foundation for breeding disease-resistant cultivars of apple in the future.

The mobilization and transport of newly fixed carbon are driven by plant water use in an experimental rainforest under drought

Non-structural carbohydrates (NSCs) are building blocks for biomass and fuel metabolic processes. However, it remains unclear how tropical forests mobilize, export, and transport NSCs to cope with extreme droughts. We combined drought manipulation and ecosystem 13CO2 pulse-labeling in an enclosed rainforest at Biosphere 2, assessed changes in NSCs, and traced newly assimilated carbohydrates in plant species with diverse hydraulic traits and canopy positions. We show that drought caused a depletion of leaf starch reserves and slowed export and transport of newly assimilated carbohydrates below ground. Drought effects were more pronounced in conservative canopy trees with limited supply of new photosynthates and relatively constant water status than in those with continual photosynthetic supply and deteriorated water status. We provide experimental evidence that local utilization, export, and transport of newly assimilated carbon are closely coupled with plant water use in canopy trees. We highlight that these processes are critical for understanding and predicting tree resistance and ecosystem fluxes in tropical forest under drought.

Cooperation of an external carbonic anhydrase and HCO3- transporter supports underwater photosynthesis in submerged leaves of the amphibious plant Hygrophila difformis

BACKGROUND AND AIMS

HCO3- can be a major carbon resource for photosynthesis in underwater environments. Here we investigate the underlying mechanism of uptake and membrane transport of HCO3- in submerged leaves of Hygrophila difformis, a heterophyllous amphibious plant. To characterize these mechanisms, we evaluated the sensitivity of underwater photosynthesis to an external carbonic anhydrase (CA) inhibitor and an anion exchanger protein inhibitor, and we attempted to identify components of the mechanism of HCO3- utilization.

METHODS

We evaluated the effects of the external CA inhibitor and anion exchanger protein inhibitor on the NaHCO3 response of photosynthetic O2 evolution in submerged leaves of H. difformis. Furthermore, we performed a comparative transcriptomic analysis between terrestrial and submerged leaves.

KEY RESULTS

Photosynthesis in the submerged leaves was decreased by both the external CA inhibitor and anion exchanger protein inhibitor, but no additive effect was observed. Among upregulated genes in submerged leaves, two α-CAs, Hdα-CA1 and Hdα-CA2, and one β-carbonic anhydrase, Hdβ-CA1, were detected. Based on their putative amino acid sequences, the α-CAs are predicted to be localized in the apoplastic region. Recombinant Hdα-CA1 and Hdβ-CA1 showed dominant CO2 hydration activity over HCO3- dehydration activity.

CONCLUSIONS

We propose that the use of HCO3- for photosynthesis in submerged leaves of H. difformis is driven by the cooperation between an external CA, Hdα-CA1, and an unidentified HCO3- transporter.

Mutation mapping of a variegated EMS tomato reveals an FtsH-like protein precursor potentially causing patches of four phenotype classes in the leaves with distinctive internal morphology

BACKGROUND

Leaf variegation is an intriguing phenomenon observed in many plant species. However, questions remain on its mechanisms causing patterns of different colours. In this study, we describe a tomato plant detected in an M2 population of EMS mutagenised seeds, showing variegated leaves with sectors of dark green (DG), medium green (MG), light green (LG) hues, and white (WH). Cells and tissues of these classes, along with wild-type tomato plants, were studied by light, fluorescence, and transmission electron microscopy. We also measured chlorophyll a/b and carotene and quantified the variegation patterns with a machine-learning image analysis tool. We compared the genomes of pooled plants with wild-type-like and mutant phenotypes in a segregating F2 population to reveal candidate genes responsible for the variegation.

RESULTS

A genetic test demonstrated a recessive nuclear mutation caused the variegated phenotype. Cross-sections displayed distinct anatomy of four-leaf phenotypes, suggesting a stepwise mesophyll degradation. DG sectors showed large spongy layers, MG presented intercellular spaces in palisade layers, and LG displayed deformed palisade cells. Electron photomicrographs of those mesophyll cells demonstrated a gradual breakdown of the chloroplasts. Chlorophyll a/b and carotene were proportionally reduced in the sectors with reduced green pigments, whereas white sectors have hardly any of these pigments. The colour segmentation system based on machine-learning image analysis was able to convert leaf variegation patterns into binary images for quantitative measurements. The bulk segregant analysis of pooled wild-type-like and variegated progeny enabled the identification of SNP and InDels via bioinformatic analysis. The mutation mapping bioinformatic pipeline revealed a region with three candidate genes in chromosome 4, of which the FtsH-like protein precursor (LOC100037730) carries an SNP that we consider the causal variegated phenotype mutation. Phylogenetic analysis shows the candidate is evolutionary closest to the Arabidopsis VAR1. The synonymous mutation created by the SNP generated a miRNA binding site, potentially disrupting the photoprotection mechanism and thylakoid development, resulting in leaf variegation.

CONCLUSION

We described the histology, anatomy, physiology, and image analysis of four classes of cell layers and chloroplast degradation in a tomato plant with a variegated phenotype. The genomics and bioinformatics pipeline revealed a VAR1-related FtsH mutant, the first of its kind in tomato variegation phenotypes. The miRNA binding site of the mutated SNP opens the way to future studies on its epigenetic mechanism underlying the variegation.

Deoxyxylulose 5-Phosphate Synthase Does Not Play a Major Role in Regulating the Methylerythritol 4-Phosphate Pathway in Poplar

The plastidic 2-C-methylerythritol 4-phosphate (MEP) pathway supplies the precursors of a large variety of essential plant isoprenoids, but its regulation is still not well understood. Using metabolic control analysis (MCA), we examined the first enzyme of this pathway, 1-deoxyxylulose 5-phosphate synthase (DXS), in multiple grey poplar (Populus × canescens) lines modified in their DXS activity. Single leaves were dynamically labeled with 13CO2 in an illuminated, climate-controlled gas exchange cuvette coupled to a proton transfer reaction mass spectrometer, and the carbon flux through the MEP pathway was calculated. Carbon was rapidly assimilated into MEP pathway intermediates and labeled both the isoprene released and the IDP+DMADP pool by up to 90%. DXS activity was increased by 25% in lines overexpressing the DXS gene and reduced by 50% in RNA interference lines, while the carbon flux in the MEP pathway was 25-35% greater in overexpressing lines and unchanged in RNA interference lines. Isoprene emission was also not altered in these different genetic backgrounds. By correlating absolute flux to DXS activity under different conditions of light and temperature, the flux control coefficient was found to be low. Among isoprenoid end products, isoprene itself was unchanged in DXS transgenic lines, but the levels of the chlorophylls and most carotenoids measured were 20-30% less in RNA interference lines than in overexpression lines. Our data thus demonstrate that DXS in the isoprene-emitting grey poplar plays only a minor part in controlling flux through the MEP pathway.

Radiocarbon Flux Measurements Provide Insight into Why a Pyroligneous Acid Product Stimulates Plant Growth

Agriculture in the 21st century faces many formidable challenges with the growing global population. Increasing demands on the planet's natural resources already tax existing agricultural practices. Today, many farmers are using biochemical treatments to improve their yields. Commercialized organic biostimulants exist in the form of pyroligneous acid generated by burning agricultural waste products. Recently, we examined the mechanisms through which a commercial pyroligneous acid product, Coriphol™, manufactured by Corigin Solutions, Inc., stimulates plant growth. During the 2023 growing season, outdoor studies were conducted in soybean to examine the effects of different Coriphol™ treatment concentrations on plant growth. Plant height, number of leaves, and leaf size were positively impacted in a dose-dependent manner with 2 gallon/acre soil treatments being optimal. At harvest, this level of treatment boosted crop yield by 40%. To gain an understanding of why Coriphol™ improves plant fitness, follow-up laboratory-based studies were conducted using radiocarbon flux analysis. Here, radioactive 11CO2 was administered to live plants and comparisons were made between untreated soybean plants and plants treated at an equivalent Coriphol™ dose of 2 gallons/acre. Leaf metabolites were analyzed using radio-high-performance liquid chromatography for [11C]-chlorophyll (Chl) a and b components, as well as [11C]-β-carotene (β-Car) where fractional yields were used to calculate metabolic rates of synthesis. Altogether, Coriphol™ treatment boosted rates of Chl a, Chl b, and β-Car biosynthesis 3-fold, 2.6-fold, and 4.7-fold, respectively, and also increased their metabolic turnover 2.2-fold, 2.1-fold, and 3.9-fold, respectively. Also, the Chl a/b ratio increased from 3.1 to 3.4 with treatment. Altogether, these effects contributed to a 13.8% increase in leaf carbon capture.

Mulberry (Morus alba L.) leaf water extract attenuates type 2 diabetes mellitus by regulating gut microbiota dysbiosis, lipopolysaccharide elevation and endocannabinoid system disorder

ETHNOPHARMACOLOGICAL RELEVANCE

Mulberry (Morus alba L.) leaf is a well-known herbal medicine and has been used to treat diabetes in China for thousands of years. Our previous studies have proven mulberry leaf water extract (MLWE) could improve type 2 diabetes mellitus (T2D). However, it is still unclear whether MLWE could mitigate T2D by regulating gut microbiota dysbiosis and thereof improve intestinal permeability and metabolic dysfunction through modulation of lipopolysaccharide (LPS) and endocannabinoid system (eCBs).

AIM OF STUDY

This study aims to explore the potential mechanism of MLWE on the regulation of metabolic function disorder of T2D mice from the aspects of gut microbiota, LPS and eCBs.

MATERIALS AND METHODS

Gut microbiota was analyzed by high-throughput 16S rRNA gene sequencing. LPS, N-arachidonoylethanolamine (AEA) and 2-ararchidonylglycerol (2-AG) contents in blood were determined by kits or liquid phase chromatography coupled with triple quadrupole tandem mass spectrometry, respectively. The receptors, enzymes or tight junction protein related to eCBs or gut barrier were detected by RT-PCR or Western blot, respectively.

RESULTS

MLWE reduced the serum levels of AEA, 2-AG and LPS, decreased the expressions of N-acylphophatidylethanolamine phospholipase D, diacylglycerol lipase-α and cyclooxygenase 2, and increased the expressions of fatty acid amide hydrolase (FAAH), N-acylethanolamine-hydrolyzing acid amidase (NAAA), alpha/beta hydrolases domain 6/12 in the liver and ileum and occludin, monoacylglycerol lipase and cannabinoid receptor 1 in the ileum of T2D mice. Furthermore, MLWE could change the abundances of the genera including Acetatifactor, Anaerovorax, Bilophila, Colidextribacter, Dubosiella, Gastranaerophilales, Lachnospiraceae_NK4A136_group, Oscillibacter and Rikenella related to LPS, AEA and/or 2-AG. Moreover, obvious improvement of MLWE treatment on serum AEA level, ileum occludin expression, and liver FAAH and NAAA expression could be observed in germ-free-mimic T2D mice.

CONCLUSION

MLWE could ameliorate intestinal permeability, inflammation, and glucose and lipid metabolism imbalance of T2D by regulating gut microbiota, LPS and eCBs.

Comprehensive deciphering the alternative splicing patterns involved in leaf morphogenesis of Liriodendron chinense

Alternative splicing (AS), a pivotal post-transcriptional regulatory mechanism, profoundly amplifies diversity and complexity of transcriptome and proteome. Liriodendron chinense (Hemsl.) Sarg., an excellent ornamental tree species renowned for its distinctive leaf shape, which resembles the mandarin jacket. Despite the documented potential genes related to leaf development of L. chinense, the underlying post-transcriptional regulatory mechanisms remain veiled. Here, we conducted a comprehensive analysis of the transcriptome to clarify the genome-wide landscape of the AS pattern and the spectrum of spliced isoforms during leaf developmental stages in L. chinense. Our investigation unveiled 50,259 AS events, involving 10,685 genes (32.9%), with intron retention as the most prevalent events. Notably, the initial stage of leaf development witnessed the detection of 804 differentially AS events affiliated with 548 genes. Although both differentially alternative splicing genes (DASGs) and differentially expressed genes (DEGs) were enriched into morphogenetic related pathways during the transition from fishhook (P2) to lobed (P7) leaves, there was only a modest degree of overlap between DASGs and DEGs. Furthermore, we conducted a comprehensively AS analysis on homologous genes involved in leaf morphogenesis, and most of which are subject to post-transcriptional regulation of AS. Among them, the AINTEGUMENTA-LIKE transcript factor LcAIL5 was characterization in detailed, which experiences skipping exon (SE), and two transcripts displayed disparate expression patterns across multiple stages. Overall, these findings yield a comprehensive understanding of leaf development regulation via AS, offering a novel perspective for further deciphering the mechanism of plant leaf morphogenesis.

Rewiring of a KNOXI regulatory network mediated by UFO underlies the compound leaf development in Medicago truncatula

Class I KNOTTED-like homeobox (KNOXI) genes are parts of the regulatory network that control the evolutionary diversification of leaf morphology. Their specific spatiotemporal expression patterns in developing leaves correlate with the degrees of leaf complexity between simple-leafed and compound-leafed species. However, KNOXI genes are not involved in compound leaf formation in several legume species. Here, we identify a pathway for dual repression of MtKNOXI function in Medicago truncatula. PINNATE-LIKE PENTAFOLIATA1 (PINNA1) represses the expression of MtKNOXI, while PINNA1 interacts with MtKNOXI and sequesters it to the cytoplasm. Further investigations reveal that UNUSUAL FLORAL ORGANS (MtUFO) is the direct target of MtKNOXI, and mediates the transition from trifoliate to pinnate-like pentafoliate leaves. These data suggest a new layer of regulation for morphological diversity in compound-leafed species, in which the conserved regulators of floral development, MtUFO, and leaf development, MtKNOXI, are involved in variation of pinnate-like compound leaves in M. truncatula.

Phenotypic and yield responses of common bean (Phaseolus vulgaris l.) varieties to different soil moisture levels

BACKGROUND

Morphological plasticity is one of the capacities of plants to modify their morphological appearance in response to external stimuli. A plant's morphology and physiology are constantly tuned to its variable surroundings by complex interactions between environmental stimuli and internal signals. In most of plant species,, such phenotypic and physiological expression varies among different varieties based on their levels of particular environmental stress conditions. However, the morphological and yield responses of common bean varieties to different environmental conditions are not well known. The purpose of the study was to evaluate morphological and yield response of common bean to soil moisture stress and to investigate the morphological mechanism by which common bean varieties tolerate fluctuations in moisture stress.

METHODS

A pot experiment was carried out to investigate the effects of different moisture levels on the phenotypic and yield responses of common bean varieties. A factorial combination of five common bean varieties (Hirna, kufanzik, Awash-1, Ado, and Chercher) and three moisture levels (control, waterlogging stress, and moisture deficit stress) was used in three replications. Moisture stress treatments were started 20 days after planting, at the trifoliate growth stage. To evaluate the response of each variety, morphological and yield data were collected at week intervals.

MAIN RESULTS

The results indicated that moisture levels and varieties had a significant influence on all growth parameters. Crop phenology was significantly influenced by the interaction effect of moisture level and variety. Exposing Hirna variety to moisture stress led to extended flowering and pod setting by 23 and 24 days, respectively, compared to the other treatments. The results showed that the phenotypic responses to moisture deficit and waterlogging stress varied between varieties. Waterlogging stress had a stronger reduction effect on the fresh weight, dry weight and leaf area of common bean varieties than moisture deficit and the control. Pods per plant, seeds per plant, grain yield per plant, and harvest index were significantly influenced by the varieties, moisture stress levels and their interaction. Except for Chercher and Hirna. However, varieties Ado, kufanzik and Awasha-1 did not show significant differences on the time of flower initiation due to moisture level. Biomass and growth in leaf fresh weight, leaf dry weight, leaf area, leaf number and plant height were significantly influenced by moisture level. When moisture deficit and waterlogging stress occurred, Ado and Awash-1 were more responsive to moisture stress than Hirna, Chercher, and Kufanzik.

CONCLUSION

Hence, Hirna and Kufanzik varieties were found to be tolerant because they produced higher yields than the Chercher, Awash-1, and Ado varieties.

The metabolic fingerprint of Scots pine-root and needle metabolites show different patterns in dying trees

The loss of leaves and needles in tree crowns and tree mortality are increasing worldwide, mostly as a result of more frequent and severe drought stress. Scots pine (Pinus sylvestris L.) is a tree species that is strongly affected by these developments in many regions of Europe and Asia. So far, changes in metabolic pathways and metabolite profiles in needles and roots on the trajectory toward mortality are unknown, although they could contribute to a better understanding of the mortality mechanisms. Therefore, we linked long-term observations of canopy defoliation and tree mortality with the characterization of the primary metabolite profile in needles and fine roots of Scots pines from a forest site in the Swiss Rhone valley. Our results show that Scots pines are able to maintain metabolic homeostasis in needles over a wide range of canopy defoliation levels. However, there is a metabolic tipping point at around 80-85% needle loss. Above this threshold, many stress-related metabolites (particularly osmoprotectants, defense compounds and antioxidants) increase in the needles, whereas they decrease in the fine roots. If this defoliation tipping point is exceeded, the trees are very likely to die within a few years. The different patterns between needles and roots indicate that mainly belowground carbon starvation impairs key functions for tree survival and suggest that this is an important factor explaining the increasing mortality of Scots pines.

MbEOMT1 regulates methyleugenol biosynthesis in Melaleuca bracteata F. Muell

Methyleugenol, a bioactive compound in the phenylpropene family, undergoes its final and crucial biosynthetic transformation when eugenol O-methyltransferase (EOMT) converts eugenol into methyleugenol. While Melaleuca bracteata F. Muell essential oil is particularly rich in methyleugenol, it contains only trace amounts of its precursor, eugenol. This suggests that the EOMT enzyme in M. bracteata is highly efficient, although it has not yet been characterized. In this study, we isolated and identified an EOMT gene from M. bracteata, termed MbEOMT1, which is primarily expressed in the flowers and leaves and is inducible by methyl jasmonate (MeJA). Subcellular localization of MbEOMT1 in the cytoplasm was detected. Through transient overexpression experiments, we found that MbEOMT1 significantly elevates the concentration of methyleugenol in M. bracteata leaves. Conversely, silencing of MbEOMT1 via virus-induced gene silencing led to a marked reduction in methyleugenol levels. Our in vitro enzymatic assays further confirmed that MbEOMT1 specifically catalyzes the methylation of eugenol. Collectively, these findings establish that the MbEOMT1 gene is critical for methyleugenol biosynthesis in M. bracteata. This study enriches the understanding of phenylpropene biosynthesis and suggests that MbEOMT1 could serve as a valuable catalyst for generating bioactive compounds in the future.

Biochemical and Transcriptome Analysis Reveals Pigment Biosynthesis Influenced Chlorina Leaf Formation in Anoectochilus roxburghii (Wall.) Lindl

Anoectochilus roxburghii (Wall.) Lindl is a perennial herb of the Orchidaceae family; a yellow-green mutant and a yellow mutant were obtained from the wild type, thereby providing good material for the study of leaf color variation. Pigment content analysis revealed that chlorophyll, carotenoids, and anthocyanin were lower in the yellow-green and yellow mutants than in the wild type. Transcriptome analysis of the yellow mutant and wild type revealed that 78,712 unigenes were obtained, and 599 differentially expressed genes (120 upregulated and 479 downregulated) were identified. Using the Kyoto Encyclopedia of Genes and Genomes pathway analysis, candidate genes involved in the anthocyanin biosynthetic pathway (five unigenes) and the chlorophyll metabolic pathway (two unigenes) were identified. Meanwhile, the low expression of the chlorophyll and anthocyanin biosynthetic genes resulted in the absence of chlorophylls and anthocyanins in the yellow mutant. This study provides a basis for similar research in other closely related species.

Physiology, genomics, and evolutionary aspects of desert plants

BACKGROUND

Despite the exposure to arid environmental conditions across the globe ultimately hampering the sustainability of the living organism, few plant species are equipped with several unique genotypic, biochemical, and physiological features to counter such harsh conditions. Physiologically, they have evolved with reduced leaf size, spines, waxy cuticles, thick leaves, succulent hydrenchyma, sclerophyll, chloroembryo, and photosynthesis in nonfoliar and other parts. At the biochemical level, they are evolved to perform efficient photosynthesis through Crassulacean acid metabolism (CAM) and C4 pathways with the formation of oxaloacetic acid (Hatch-Slack pathway) instead of the C3 pathway. Additionally, comparative genomics with existing data provides ample evidence of the xerophytic plants' positive selection to adapt to the arid environment. However, adding more high-throughput sequencing of xerophyte plant species is further required for a comparative genomic study toward trait discovery related to survival. Learning from the mechanism to survive in harsh conditions could pave the way to engineer crops for future sustainable agriculture.

AIM OF THE REVIEW

The distinct physiology of desert plants allows them to survive in harsh environments. However, the genomic composition also contributes significantly to this and requires great attention. This review emphasizes the physiological and genomic adaptation of desert plants. Other important parameters, such as desert biodiversity and photosynthetic strategy, are also discussed with recent progress in the field. Overall, this review discusses the different features of desert plants, which prepares them for harsh conditions intending to translate knowledge to engineer plant species for sustainable agriculture.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review comprehensively presents the physiology, molecular mechanism, and genomics of desert plants aimed towards engineering a sustainable crop.

Seedlings of Poncirus trifoliata exhibit tissue-specific detoxification in response to NH4 + toxicity

Ammonium nitrogen (NH4 +-N) is essential for fruit tree growth, but the impact of excess NH4 +-N from fertilizer on evergreen citrus trees is unclear. In a climate chamber, 8-month-old citrus plants were exposed to five different hydroponic NH4 +-N concentrations (0, 5, 10, 15 and 20 mm) for 1 month to study effects of NH4 +-N on growth characteristics, N uptake, metabolism, antioxidant enzymes and osmotic regulatory substances. Application of 10 mm NH4 +-N adversely affected root plasma membrane integrity, root physiological functions, and plant biomass. MDA, CAT, POD, APX and SOD content were significantly correlated with leaf N metabolic enzyme activity (GOGAT, GDH, GS and NR). GDH was the primary enzyme involved in NH4 +-N assimilation in leaves, while the primary pathway involved in roots was GS-GOGAT. Under comparatively high NH4 + addition, roots were the main organs involved in NH4 + utilization in citrus seedlings. Our results demonstrated that variations in NH4 + concentration and enzyme activity in various organs are associated with more effective N metabolism in roots than in leaves to prevent NH4 + toxicity in evergreen woody citrus plants. These results provide insight into the N forms used by citrus plants that are important for N fertilizer management.

Comparative analysis of PLATZ transcription factors in six poplar species and analysis of the role of PtrPLATZ14 in leaf development

Plant AT-rich sequence and zinc-binding (PLATZ) proteins are a class of plant-specific transcription factor that play a crucial role in plant growth, development, and stress response. However, the evolutionary relationship of the PLATZ gene family across the Populus genus and the biological functions of the PLATZ protein require further investigation. In this study, we identified 133 PLATZ genes from six Populus species belonging to four Populus sections. Synteny analysis of the PLATZ gene family indicated that whole genome duplication events contributed to the expansion of the PLATZ family. Among the nine paralogous pairs, the protein structure of PtrPLATZ14/18 pair exhibited significant differences with others. Through gene expression patterns and co-expression networks, we discovered divergent expression patterns and sub-networks, and found that the members of pair PtrPLATZ14/18 might play different roles in the regulation of macromolecule biosynthesis and modification. Furthermore, we found that PtrPLATZ14 regulates poplar leaf development by affecting cell size control genes PtrGRF/GIF and PtrTCP. In conclusion, our study provides a theoretical foundation for exploring the evolution relationships and functions of the PLATZ gene family within Populus species and provides insights into the function and potential mechanism of PtrPLATZ14 in leaf morphology that were diverse across the Populus genus.

Potassium attenuates drought damage by regulating sucrose metabolism and gene expression in sesame leaf

Drought has been considered the most restrictive environmental constraint on agricultural production worldwide. Photosynthetic carbohydrate metabolism is a critical biochemical process connected with crop production and quality traits. A pot experiment was carried out under four potassium (K) rates (0, 0.75, 1.5 and 2.25 g pot-1 of K, respectively) and two water regimes to investigate the role of K in activating defense mechanisms on sucrose metabolism against drought damage in sesame. The soil moisture contents are 75 ± 5% (well-watered, WW) and 45 ± 5% (drought stress, DS) of field capacity respectively. The results showed that DS plants without K application have lower activities of ribulose-1,5-bisphosphate carboxylase (Rubisco), sucrose phosphate synthase (SPS), soluble acid invertase (SAI), and chlorophyll content and higher activity of sucrose synthase (SuSy), which resulted in declined synthesis and distribution of photosynthetic products to reproductive organs. Under drought, there was a significant positive correlation between leaf sucrose metabolizing enzymes and sucrose content. Plants subjected to drought stress increased the concentrations of soluble sugar and sucrose to produce osmo-protectants and energy sources for plants acclimating to stress but decreased starch content. Conversely, K application enhanced the carbohydrate metabolism, biomass accumulation and partitioning, thereby contributing to higher seed oil and protein yield (28.8%-43.4% and 27.5%-40.7%) as compared to K-deficiency plants. The positive impacts of K application enhanced as increasing K rates, and it was more pronounced in drought conditions. Furthermore, K application upregulated the gene expression of SiMYB57, SiMYB155, SiMYB176 and SiMYB192 while downregulated SiMYB108 and SiMYB171 in drought conditions, which may help to alleviate drought susceptibility. Conclusively, our study illustrated that the enhanced photo-assimilation and translocation process caused by the changes in sucrose metabolism activities under K application as well as regulation of MYB gene expression contributes towards drought resistance of sesame.

Effects of capsaicin loads on the properties of capsicum leaf protein-based nanocellulose composite films

This study aims to enhance the functionality of conventional protein-based nanocellulose composite films (PNCF) to meet the high demand for natural antimicrobial packaging films. Capsicum leaf protein (CLP) and cellulose nanocrystals (CNCs) extracted from capsicum leaves were used as raw materials. Capsaicin, an essential antibacterial active ingredient in the capsicum plant, was used as an additive. The influence of different capsaicin loads on PNCF physicochemical and material properties was investigated under alkaline conditions. The results show that all film-forming liquids (FFLs) are non-Newtonian fluids with shear thinning behavior. When the capsaicin loading exceeds 20 %, the surface microstructure of PNCF changes from dense lamellar to rod-like. Capsaicin did not alter the PNCF crystal structure, thermal stability or chemical bonding. Capsaicin can be loaded onto the PNCF surface by intermolecular hydrogen bonding reactions with CLP and CNC, preserving capsaicin's biological activity. With increasing capsaicin loads from 0 % to 50 %, the mechanical and hydrophobic properties of PNCF decreased, whereas the diameter of the inhibition zone increased. All PNCFs have UV-blocking properties with potential applications in developing biodegradable food packaging materials. The results of this study provide a theoretical basis for the high-value utilization of capsicum cultivation waste and the preparation of novel PNCF.

Determination of process parameters and precipitation methods for potential large-scale production of sugar beet leaf protein concentrate

BACKGROUND

Sugar beet is one of the most produced industrial plants in the world, and during manufacturing it produces a large quantity of leaf waste. Because this waste is rich in protein, this study aimed to identify an efficient method for producing large-scale protein concentrate from sugar beet leaves.

RESULTS

Results showed that protein extraction from fresh leaves was more effective than from dried leaves. Maximum protein extraction was achieved at pH 9, compared with pH 7 or 8. Blanching as a pretreatment reduced protein yield during isoelectric precipitation, with a yield of 2.31% compared to 20.20% without blanching. Consequently, blanching was excluded from the extraction process. After extraction, isoelectric precipitation, heat coagulation, and isoelectric-ammonium sulfate precipitation were compared. Although the latter resulted in the highest protein yield, Fourier transform infrared analysis revealed that excessive salt was not removed during dialysis, making it unsuitable for scale-up due to its additional cost and complexity. Therefore, isoelectric precipitation was selected as the appropriate method for protein precipitation from sugar beet leaves. To increase yield, extractions were assisted by ultrasound or enzyme addition. Ultrasound-assisted extraction resulted in an increased protein yield from 20.20% to 28.60%, while Pectinex Ultra SP-L-assisted extraction was the most effective, increasing protein yield from 20.20% to 38.09%.

CONCLUSION

Proteins were extracted from fresh sugar beet leaves using optimum conditions (50 °C, 30 min, pH 9) and precipitated at isoelectric point, with enzymatic-assisted extraction yielding the maximum protein recovery. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Leaf diffusional capacity largely contributes to the reduced photosynthesis in rice plants under magnesium deficiency

Numerous studies have clarified the impacts of magnesium (Mg) on leaf photosynthesis from the perspectives of protein synthesis, enzymes activation and carbohydrate partitioning. However, it still remains largely unknown how stomatal and mesophyll conductances (gs and gm, respectively) are regulated by Mg. In the present study, leaf gas exchanges, leaf hydraulic parameters, leaf structural traits and cell wall composition were examined in rice plants grown under high and low Mg treatments to elucidate the impacts of Mg on gs and gm. Our results showed that reduction of leaf photosynthesis under Mg deficiency was mainly caused by the decreased gm, followed by reduced leaf biochemical capacity and gs, and leaf outside-xylem hydraulic conductance (Kox) was the major factor restricting gs under Mg deficiency. Moreover, increased leaf hemicellulose, lignin and pectin contents and decreased cell wall effective porosity were observed in low Mg plants relative to high Mg plants. These results suggest that Kox and cell wall composition play important roles in regulating gs and gm, respectively, in rice plants under Mg shortages.

The isoprene-responsive phosphoproteome provides new insights into the putative signalling pathways and novel roles of isoprene

Many plants, especially trees, emit isoprene in a highly light- and temperature-dependent manner. The advantages for plants that emit, if any, have been difficult to determine. Direct effects on membranes have been disproven. New insights have been obtained by RNA sequencing, proteomic and metabolomic studies. We determined the responses of the phosphoproteome to exposure of Arabidopsis leaves to isoprene in the gas phase for either 1 or 5 h. Isoprene effects that were not apparent from RNA sequencing and other methods but were apparent in the phosphoproteome include effects on chloroplast movement proteins and membrane remodelling proteins. Several receptor kinases were found to have altered phosphorylation levels. To test whether potential isoprene receptors could be identified, we used molecular dynamics simulations to test for proteins that might have strong binding to isoprene and, therefore might act as receptors. Although many Arabidopsis proteins were found to have slightly higher binding affinities than a reference set of Homo sapiens proteins, no specific receptor kinase was found to have a very high binding affinity. The changes in chloroplast movement, photosynthesis capacity and so forth, found in this work, are consistent with isoprene responses being especially useful in the upper canopy of trees.

Depicting the genetic and metabolic panorama of chemical diversity in the tea plant

As a frequently consumed beverage worldwide, tea is rich in naturally important bioactive metabolites. Combining genetic, metabolomic and biochemical methodologies, here, we present a comprehensive study to dissect the chemical diversity in tea plant. A total of 2837 metabolites were identified at high-resolution with 1098 of them being structurally annotated and 63 of them were structurally identified. Metabolite-based genome-wide association mapping identified 6199 and 7823 metabolic quantitative trait loci (mQTL) for 971 and 1254 compounds in young leaves (YL) and the third leaves (TL), respectively. The major mQTL (i.e., P < 1.05 × 10-5, and phenotypic variation explained (PVE) > 25%) were further interrogated. Through extensive annotation of the tea metabolome as well as network-based analysis, this study broadens the understanding of tea metabolism and lays a solid foundation for revealing the natural variations in the chemical composition of the tea plant. Interestingly, we found that galloylations, rather than hydroxylations or glycosylations, were the largest class of conversions within the tea metabolome. The prevalence of galloylations in tea is unusual, as hydroxylations and glycosylations are typically the most prominent conversions of plant specialized metabolism. The biosynthetic pathway of flavonoids, which are one of the most featured metabolites in tea plant, was further refined with the identified metabolites. And we demonstrated the further mining and interpretation of our GWAS results by verifying two identified mQTL (including functional candidate genes CsUGTa, CsUGTb, and CsCCoAOMT) and completing the flavonoid biosynthetic pathway of the tea plant.

Salicylic acid- and ethylene-dependent effects of the ER stress-inducer tunicamycin on the photosynthetic light reactions in tomato plants

Plant hormones such as ethylene (ET) and salicylic acid (SA) have an elementary role in the regulation of ER stress and unfolded protein response (UPR) in plants via modulating defence responses or inducing oxidative stress. Chloroplasts can be sources and targets of reactive oxygen species (ROS) that affect photosynthetic efficiency, which has not been investigated under tunicamycin (Tm)-induced ER stress. In this study, the direct and indirect effects of Tm on chloroplastic ROS production were first investigated in leaves of wild-type tomato (Solanum lycopersicum L.) plants. Secondly changes in activities of photosystem II and I were analysed under Tm exposure and after application of the chemical chaperone 4-phenylbutyrate (PBA) in different genotypes, focusing on the regulatory role of SA and ET Tm treatments significantly but indirectly induced ROS production in tomato leaves and in parallel it decreased the effective quantum yield of PSII [Y(II)] and PSI [Y(I)], as well as the photochemical quenching coefficient (qP) and the quantum yield of non-photochemical energy dissipation in PSI due to acceptor-side limitation [Y(NA)]. At the same time, Tm increased non-photochemical quenching (NPQ) and cyclic electron flow (CEF) in tomato leaves after 24 h. However, the photosynthetic activity of the SA hydroxylase-overexpressing NahG tomato plants was more severely affected by Tm as compared to wild-type and ET-insensitive Never ripe (Nr) plants. These results suggest the protective role of SA in the regulation of photosynthetic activity contributing to UPR and the survival of plants under ER stress. Interestingly, the activation of photoprotective mechanisms by NPQ was independent of SA but dependent on active ET signalling under ER stress, whereas CEF was reduced by ET due to its higher ratio in Nr plants.

Systemic stomatal responses in plants: Coordinating development, stress, and pathogen defense under a changing climate

To successfully survive, develop, grow and reproduce, multicellular organisms must coordinate their molecular, physiological, developmental and metabolic responses among their different cells and tissues. This process is mediated by cell-to-cell, vascular and/or volatile communication, and involves electric, chemical and/or hydraulic signals. Within this context, stomata serve a dual role by coordinating their responses to the environment with their neighbouring cells at the epidermis, but also with other stomata present on other parts of the plant. As stomata represent one of the most important conduits between the plant and its above-ground environment, as well as directly affect photosynthesis, respiration and the hydraulic status of the plant by controlling its gas and vapour exchange with the atmosphere, coordinating the overall response of stomata within and between different leaves and tissues plays a cardinal role in plant growth, development and reproduction. Here, we discuss different examples of local and systemic stomatal coordination, the different signalling pathways that mediate them, and the importance of systemic stomatal coordination to our food supply, ecosystems and weather patterns, under our changing climate. We further discuss the potential biotechnological implications of regulating systemic stomatal responses for enhancing agricultural productivity in a warmer and CO2 -rich environment.

Combining PSII photochemistry and hydraulics improves predictions of photosynthesis and water use from mild to lethal drought

Rising temperatures and increases in drought negatively impact the efficiency and sustainability of both agricultural and forest ecosystems. Although hydraulic limitations on photosynthesis have been extensively studied, a solid understanding of the links between whole plant hydraulics and photosynthetic processes at the cellular level under changing environmental conditions is still missing, hampering our predictive power for plant mortality. Here, we examined plant hydraulic traits and CO2 assimilation rate under progressive water limitation by implementing Photosystem II (PSII) dynamics with a whole plant process model (TREES). The photosynthetic responses to plant water status were parameterized based on measurements of chlorophyll a fluorescence, gas exchange and water potential for Brassica rapa (R500) grown in a greenhouse under fully watered to lethal drought conditions. The updated model significantly improved predictions of photosynthesis, stomatal conductance and leaf water potential. TREES with PSII knowledge predicted a larger hydraulic safety margin and a decrease in percent loss of conductivity. TREES predicted a slower decrease in leaf water potential, which agreed with measurements. Our results highlight the pressing need for incorporating PSII drought photochemistry into current process models to capture cross-scale plant water dynamics from cell to whole plant level.

UHPLC-MS/MS and GC-MS Metabolic Profiling of a Medicinal Flourensia Fiebrigii Chemotype

The comparative metabolic profiling and their biological properties of eight extracts obtained from diverse parts (leaves, flowers, roots) of the medicinal plant Flourensia fiebrigii S.F. Blake, a chemotype growing in highland areas (2750 m a.s.l.) of northwest Argentina, were investigated. The extracts were analysed by GC-MS and UHPLC-MS/MS. GC-MS analysis revealed the presence of encecalin (relative content: 24.86 %) in ethereal flower extract (EF) and this benzopyran (5.93 %) together sitosterol (11.35 %) in the bioactive ethereal leaf exudate (ELE). By UHPLC-MS/MS the main compounds identified in both samples were: limocitrin, (22.31 %), (2Z)-4,6-dihydroxy-2-[(4-hydroxy-3,5-dimethoxyphenyl)methylidene]-1-benzofuran-3-one (21.31 %), isobavachin (14.47 %), naringenin (13.50 %), and sternbin, (12.49 %). Phytocomplexes derived from aerial parts exhibited significant activity against biofilm production of Pseudomonas aeruginosa and Staphylococcus aureus, reaching inhibitions of 74.7-99.9 % with ELE (50 μg/mL). Notably, the extracts did not affect nutraceutical and environmental bacteria, suggesting a selective activity. ELE also showed the highest reactive species scavenging ability. This study provides valuable insights into the potential applications of this chemotype.

Determination of the maximum bioaccumulation capacity of various metals in leaves of two Tillandsia species

Tillandsia species are plants from the Bromeliaceae family which display biomonitoring capacities in both active and passive modes. The bioaccumulation potential of Tillandsia aeranthos (Loisiel.) Desf. and Tillandsia bergeri Mez acclimated to Southern/Mediterranean Europe has never been studied. More generally, few studies have detailed the maximum accumulation potential of Tillandsia leaves through controlled experiments. The aim of this study is to evaluate the maximum accumulation values of seven metals (Co, Cu, Mn, Ni, Pb, Pt, and Zn) in T. aeranthos and T. bergeri leaves. Plants were immersed in different mono elemental metallic solutions of Co (II), Cu (II), Mn (II), Ni (II), Pb (II), Pt (IV), and Zn (II) ions at different concentrations. In addition, cocktail solutions of these seven metals at different concentrations were prepared to study the main differences and the potential selectivity between metals. After exposure, the content of these metals in the leaves were measured by inductively coupled plasma-optical emission spectrometry. Data sets were evaluated by a fitted regression hyperbola model and principal component analysis, maximum metal loading capacity, and thermodynamic affinity constant were determined. The results showed important differences between the two species, with T. bergeri demonstrating higher capacity and affinity for metals than T. aeranthos. Furthermore, between the seven metals, Pb and Ni showed higher enrichment factors (EF). T. bergeri might be a better bioaccumulator than T. aeranthos with marked selectivity for Pb and Ni, metals of concern in air quality biomonitoring.

Overexpression of OsACL5 triggers environmentally-dependent leaf rolling and reduces grain size in rice

Major polyamines include putrescine, spermidine, spermine and thermospermine, which play vital roles in growth and adaptation against environmental changes in plants. Thermospermine (T-Spm) is synthetised by ACL5. The function of ACL5 in rice is still unknown. In this study, we used a reverse genetic strategy to investigate the biological function of OsACL5. We generated several knockout mutants by pYLCRISPR/Cas9 system and overexpressing (OE) lines of OsACL5. Interestingly, the OE plants exhibited environmentally-dependent leaf rolling, smaller grains, lighter 1000-grain weight and reduction in yield per plot. The area of metaxylem vessels of roots and leaves of OE plants were significantly smaller than those of WT, which possibly caused reduction in leaf water potential, resulting in leaf rolling with rise in the environmental temperature and light intensity and decrease in humidity. Additionally, the T-Spm contents were markedly increased by over ninefold whereas the ethylene evolution was reduced in OE plants, suggesting that T-Spm signalling pathway interacts with ethylene pathway to regulate multiple agronomic characters. Moreover, the osacl5 exhibited an increase in grain length, 1000-grain weight, and yield per plot. OsACL5 may affect grain size via mediating the expression of OsDEP1, OsGS3 and OsGW2. Furthermore, haplotypes analysis indicated that OsACL5 plays a conserved function on regulating T-Spm levels during the domestication of rice. Our data demonstrated that identification of OsACL5 provides a theoretical basis for understanding the physiological mechanism of T-Spm which may play roles in triggering environmentally dependent leaf rolling; OsACL5 will be an important gene resource for molecular breeding for higher yield.

Long term co-application of biochar and fertilizer could increase soybean yield under continuous cropping: insights from photosynthetic physiology

BACKGROUND

Photosynthesis is the key to crop yield. The effect of biochar on photosynthetic physiology and soybean yield under continuous cropping is unclear. We conducted a long-term field experiment to investigate the effects of co-application of biochar and fertilizer (BCAF) on these parameters. Five treatments were established: F2 (fertilizer), B1F1 (3 t hm-2 biochar plus fertilizer), B1F2 (3 t hm-2 biochar plus reduced fertilizer), B2F1 (6 t hm-2 biochar plus fertilizer), and B2F2 (6 t hm-2 biochar plus reduced fertilizer).

RESULTS

BCAF increased chlorophyll and leaf area, enhancing soybean photosynthesis. The net photosynthetic rate (Pn ), transpiration rate (Tr ), stomatal conductance (Gs ), water use efficiency (WUE) and intercellular carbon dioxide (CO2 ) concentration (Ci ) were enhanced by BCAF. In addition, BCAF improved soybean photosystem II (PSII) photosynthetic performance, driving force, potential photochemical efficiency (Fv /F0 ), and quantum yield of electron transfer (φE0 ). Furthermore, BCAF enhanced the accumulation of photosynthetic products, such as soluble proteins, soluble sugars and sucrose content, resulting in higher leaf dry weight. Consequently, BCAF increased the soybean yield, with the highest increase of 41.54% in B2F1. The correlation analysis revealed positive relationships between soybean yield and chlorophyll, leaf area, maximal quantum yield of PSII (Fv /Fm ), electron transport flux per cross-section at t = 0 (ET0 /CS0 ), trapped energy flux per cross-section at t = 0 (TR0 /CS0 ), composite blade driving force (DFTotal ), and leaf dry weight.

CONCLUSIONS

We demonstrated that long-term BCAF enhances soybean photosynthesis under continuous planting, reduces fertilizer use and increases yield. This study reveals a novel way and theory to sustainably increase soybean productivity. © 2023 Society of Chemical Industry.

UMAMIT44 is a key player in glutamate export from Arabidopsis chloroplasts

Selective partitioning of amino acids among organelles, cells, tissues, and organs is essential for cellular metabolism and plant growth. Nitrogen assimilation into glutamine and glutamate and de novo biosynthesis of most protein amino acids occur in chloroplasts; therefore, various transport mechanisms must exist to accommodate their directional efflux from the stroma to the cytosol and feed the amino acids into the extraplastidial metabolic and long-distance transport pathways. Yet, Arabidopsis (Arabidopsis thaliana) transporters functioning in plastidial export of amino acids remained undiscovered. Here, USUALLY MULTIPLE ACIDS MOVE IN AND OUT TRANSPORTER 44 (UMAMIT44) was identified and shown to function in glutamate export from Arabidopsis chloroplasts. UMAMIT44 controls glutamate homeostasis within and outside of chloroplasts and influences nitrogen partitioning from leaves to sinks. Glutamate imbalances in chloroplasts and leaves of umamit44 mutants impact cellular redox state, nitrogen and carbon metabolism, and amino acid (AA) and sucrose supply of growing sinks, leading to negative effects on plant growth. Nonetheless, the mutant lines adjust to some extent by upregulating alternative pathways for glutamate synthesis outside the plastids and by mitigating oxidative stress through the production of other amino acids and antioxidants. Overall, this study establishes that the role of UMAMIT44 in glutamate export from chloroplasts is vital for controlling nitrogen availability within source leaf cells and for sink nutrition, with an impact on growth and seed yield.

MicroRNA397 promotes rice flowering by regulating the photorespiration pathway

The precise timing of flowering plays a pivotal role in ensuring successful plant reproduction and seed production. This process is intricately governed by complex genetic networks that integrate internal and external signals. This study delved into the regulatory function of microRNA397 (miR397) and its target gene LACCASE-15 (OsLAC15) in modulating flowering traits in rice (Oryza sativa). Overexpression of miR397 led to earlier heading dates, decreased number of leaves on the main stem, and accelerated differentiation of the spikelet meristem. Conversely, overexpression of OsLAC15 resulted in delayed flowering and prolonged vegetative growth. Through biochemical and physiological assays, we uncovered that miR397-OsLAC15 had a profound impact on carbohydrate accumulation and photosynthetic assimilation, consequently enhancing the photosynthetic intensity in miR397-overexpressing rice plants. Notably, we identified that OsLAC15 is at least partially localized within the peroxisome organelle, where it regulates the photorespiration pathway. Moreover, we observed that a high CO2 concentration could rescue the late flowering phenotype in OsLAC15-overexpressing plants. These findings shed valuable insights into the regulatory mechanisms of miR397-OsLAC15 in rice flowering and provided potential strategies for developing crop varieties with early flowering and high-yield traits through genetic breeding.

m6A RNA methylation counteracts dark-induced leaf senescence in Arabidopsis

Senescence is an important physiological process which directly affects many agronomic traits in plants. Senescence induces chlorophyll degradation, phytohormone changes, cellular structure damage, and altered gene regulation. Although these physiological outputs are well defined, the molecular mechanisms employed are not known. Using dark-induced leaf senescence (DILS) as the experimental system, we investigated the role of N6-methyladenosine (m6A) mRNA methylation during senescence in Arabidopsis (Arabidopsis thaliana). Plants compromised in m6A machinery components like METHYLTRANSFERASE A (mta mutant) and VIRILIZER1 (vir-1 mutant) showed an enhanced DILS phenotype. This was accompanied by compromised chloroplast and photosynthesis performance in mta as well as accumulation of senescence-promoting camalexin and phytohormone jasmonic acid after dark treatment. m6A levels increased during DILS and destabilized senescence-related transcripts thereby preventing premature aging. Due to inefficient decay, senescence-related transcripts like ORESARA1 (ORE1), SENESCENCE-ASSOCIATED GENE 21 (SAG21), NAC-like, activated by AP3/PI (NAP), and NONYELLOWING 1 (NYE1) over-accumulated in mta thereby causing accelerated senescence during DILS. Overall, our data propose that m6A modification is involved in regulating the biological response to senescence in plants, providing targets for engineering stress tolerance of crops.