CBSX3-Trxo-2 regulates ROS generation of mitochondrial complex II (succinate dehydrogenase) in Arabidopsis

Promotion of apoplastic oxidative burst by artificially selected GhCBSX3A enhances Verticillium dahliae resistance in upland cotton

Verticillium wilt (VW) is a devasting disease affecting various plants, including upland cotton, a crucial fiber crop. Despite its impact, the genetic basis underlying cotton's susceptibility or defense against VW remains unclear. Here, we conducted a genome-wide association study on VW phenotyping in upland cotton and identified a locus on A13 that is significantly associated with VW resistance. We then identified a cystathionine β-synthase domain gene at A13 locus, GhCBSX3A, which was induced by Verticillium dahliae. Functional analysis, including expression silencing in cotton and overexpression in Arabidopsis thaliana, confirmed that GhCBSX3A is a causal gene at the A13 locus, enhancing SAR-RBOHs-mediated apoplastic oxidative burst. We found allelic variation on the TATA-box of GhCBSX3A promoter attenuated its expression in upland cotton, thereby weakening VW resistance. Interestingly, we discovered that altered artificial selection of GhCBSX3A_R (an elite allele for VW) under different VW pressures during domestication and other improved processes allows specific human needs to be met. Our findings underscore the importance of GhCBSX3A in response to VW, and we propose a model for defense-associated genes being selected depending on the pathogen's pressure. The identified locus and gene serve as promising targets for VW resistance enhancement in cotton through genetic engineering.

ATP Hydrolases Superfamily Protein 1 (ASP1) Maintains Root Stem Cell Niche Identity through Regulating Reactive Oxygen Species Signaling in Arabidopsis

The maintenance of the root stem cell niche identity in Arabidopsis relies on the delicate balance of reactive oxygen species (ROS) levels in root tips; however, the intricate molecular mechanisms governing ROS homeostasis within the root stem cell niche remain unclear. In this study, we unveil the role of ATP hydrolase superfamily protein 1 (ASP1) in orchestrating root stem cell niche maintenance through its interaction with the redox regulator cystathionine β-synthase domain-containing protein 3 (CBSX3). ASP1 is exclusively expressed in the quiescent center (QC) cells and governs the integrity of the root stem cell niche. Loss of ASP1 function leads to enhanced QC cell division and distal stem cell differentiation, attributable to reduced ROS levels and diminished expression of SCARECROW and SHORT ROOT in root tips. Our findings illuminate the pivotal role of ASP1 in regulating ROS signaling to maintain root stem cell niche homeostasis, achieved through direct interaction with CBSX3.

QTL Verification and Candidate Gene Screening of Fiber Quality and Lint Percentage in the Secondary Segregating Population of Gossypium hirsutum

Fiber quality traits, especially fiber strength, length, and micronaire (FS, FL, and FM), have been recognized as critical fiber attributes in the textile industry, while the lint percentage (LP) was an important indicator to evaluate the cotton lint yield. So far, the genetic mechanism behind the formation of these traits is still unclear. Quantitative trait loci (QTL) identification and candidate gene validation provide an effective methodology to uncover the genetic and molecular basis of FL, FS, FM, and LP. A previous study identified three important QTL/QTL cluster loci, harboring at least one of the above traits on chromosomes A01, A07, and D12 via a recombinant inbred line (RIL) population derived from a cross of Lumianyan28 (L28) × Xinluzao24 (X24). A secondary segregating population (F2) was developed from a cross between L28 and an RIL, RIL40 (L28 × RIL40). Based on the population, genetic linkage maps of the previous QTL cluster intervals on A01 (6.70-10.15 Mb), A07 (85.48-93.43 Mb), and D12 (0.40-1.43 Mb) were constructed, which span 12.25, 15.90, and 5.56 cM, with 2, 14, and 4 simple sequence repeat (SSR) and insertion/deletion (Indel) markers, respectively. QTLs of FL, FS, FM, and LP on these three intervals were verified by composite interval mapping (CIM) using WinQTL Cartographer 2.5 software via phenotyping of F2 and its derived F2:3 populations. The results validated the previous primary QTL identification of FL, FS, FM, and LP. Analysis of the RNA-seq data of the developing fibers of L28 and RIL40 at 10, 20, and 30 days post anthesis (DPA) identified seven differentially expressed genes (DEGs) as potential candidate genes. qRT-PCR verified that five of them were consistent with the RNA-seq result. These genes may be involved in regulating fiber development, leading to the formation of FL, FS, FM, and LP. This study provides an experimental foundation for further exploration of these functional genes to dissect the genetic mechanism of cotton fiber development.

Integration of GWAS and RNA-Seq Analysis to Identify SNPs and Candidate Genes Associated with Alkali Stress Tolerance at the Germination Stage in Mung Bean

Soil salt-alkalization seriously impacts crop growth and productivity worldwide. Breeding and applying tolerant varieties is the most economical and effective way to address soil alkalization. However, genetic resources for breeders to improve alkali tolerance are limited in mung bean. Here, a genome-wide association study (GWAS) was performed to detect alkali-tolerant genetic loci and candidate genes in 277 mung bean accessions during germination. Using the relative values of two germination traits, 19 QTLs containing 32 SNPs significantly associated with alkali tolerance on nine chromosomes were identified, and they explained 3.6 to 14.6% of the phenotypic variance. Moreover, 691 candidate genes were mined within the LD intervals containing significant trait-associated SNPs. Transcriptome sequencing of alkali-tolerant accession 132-346 under alkali and control conditions after 24 h of treatment was conducted, and 2565 DEGs were identified. An integrated analysis of the GWAS and DEGs revealed six hub genes involved in alkali tolerance responses. Moreover, the expression of hub genes was further validated by qRT-PCR. These findings improve our understanding of the molecular mechanism of alkali stress tolerance and provide potential resources (SNPs and genes) for the genetic improvement of alkali tolerance in mung bean.

Genome-wide identification of cystathionine beta synthase genes in wheat and its relationship with anther male sterility under heat stress

Cystathionine beta synthase (CBS) domains containing proteins (CDCPs) plays an important role in plant development through regulation of the thioredoxin system, as well as its ability to respond to biotic and abiotic stress conditions. Despite this, no systematic study has examined the wheat CBS gene family and its relation to high temperature-induced male sterility. In this study, 66 CBS family members were identified in the wheat genome, and their gene or protein sequences were used for subsequent analysis. The TaCBS gene family was found to be unevenly distributed on 21 chromosomes, and they were classified into four subgroups according to their gene structure and phylogeny. The results of collinearity analysis showed that there were 25 shared orthologous genes between wheat, rice and Brachypodium distachyon, and one shared orthologous gene between wheat, millet and barley. The cis-regulatory elements of the TaCBS were related to JA, IAA, MYB, etc. GO and KEGG pathway analysis identified these TaCBS genes to be associated with pollination, reproduction, and signaling and cellular processes, respectively. A heatmap of wheat plants based on transcriptome data showed that TaCBS genes were expressed to a higher extent in spikelets relative to other tissues. In addition, 29 putative tae-miRNAs were identified, targeting 41 TaCBS genes. Moreover, qRT-PCR validation of six TaCBS genes indicated their critical role in anther development, as five of them were expressed at lower levels in heat-stressed male sterile anthers than in Normal anthers. Together with anther phenotypes, paraffin sections, starch potassium iodide staining, and qRT-PCR data, we hypothesized that the TaCBS gene has a very important connection with the heat-stressed sterility process in wheat, and these data provide a basis for further insight into their relationship.

The Shared Proteome of the Apomictic Fern Dryopteris affinis ssp. affinis and Its Sexual Relative Dryopteris oreades

Ferns are a diverse evolutionary lineage, sister to the seed plants, which is of great ecological importance and has a high biotechnological potential. Fern gametophytes represent one of the simplest autotrophic, multicellular plant forms and show several experimental advantages, including a simple and space-efficient in vitro culture system. However, the molecular basis of fern growth and development has hardly been studied. Here, we report on a proteomic study that identified 417 proteins shared by gametophytes of the apogamous fern Dryopteris affinis ssp. affinis and its sexual relative Dryopteris oreades. Most proteins are predicted to localize to the cytoplasm, the chloroplast, or the nucleus, and are linked to enzymatic, binding, and structural activities. A subset of 145 proteins are involved in growth, reproduction, phytohormone signaling and biosynthesis, and gene expression, including homologs of SHEPHERD (SHD), HEAT SHOCK PROTEIN 90-5 (CR88), TRP4, BOBBER 1 (BOB1), FLAVONE 3'-O-METHYLTRANSFERASE 1 (OMT1), ZEAXANTHIN EPOXIDASE (ABA1), GLUTAMATE DESCARBOXYLASE 1 (GAD), and dsRNA-BINDING DOMAIN-LIKE SUPERFAMILY PROTEIN (HLY1). Nearly 25% of the annotated proteins are associated with responses to biotic and abiotic stimuli. As for biotic stress, the proteins PROTEIN SGT1 HOMOLOG B (SGT1B), SUPPRESSOR OF SA INSENSITIVE2 (SSI2), PHOSPHOLIPASE D ALPHA 1 (PLDALPHA1), SERINE/THREONINE-PROTEIN KINASE SRK2E (OST1), ACYL CARRIER PROTEIN 4 (ACP4), and NONHOST RESISTANCE TO P. S. PHASEOLICOLA1 (GLPK) are worth mentioning. Regarding abiotic stimuli, we found proteins associated with oxidative stress: SUPEROXIDE DISMUTASE[CU-ZN] 1 (CSD1), and GLUTATHIONE S-TRANSFERASE U19 (GSTU19), light intensity SERINE HYDROXYMETHYLTRANSFERASE 1 (SHM1) and UBIQUITIN-CONJUGATING ENZYME E2 35 (UBC35), salt and heavy metal stress included MITOCHONDRIAL PHOSPHATE CARRIER PROTEIN 3 (PHT3;1), as well as drought and thermotolerance: LEA7, DEAD-BOX ATP-DEPENDENT RNA HELICASE 38 (LOS4), and abundant heat-shock proteins and other chaperones. In addition, we identified interactomes using the STRING platform, revealing protein-protein associations obtained from co-expression, co-occurrence, text mining, homology, databases, and experimental datasets. By focusing on ferns, this proteomic study increases our knowledge on plant development and evolution, and may inspire future applications in crop species.

Mitochondrial functions in plant immunity

Mitochondria are energy factories of cells and are important for intracellular interactions with other organelles. Emerging evidence indicates that mitochondria play essential roles in the response to pathogen infection. During infection, pathogens deliver numerous enzymes and effectors into host cells, and some of these effectors target mitochondria, altering mitochondrial morphology, metabolism, and functions. To defend against pathogen attack, mitochondria are actively involved in changing intracellular metabolism, hormone-mediated signaling, and signal transduction, producing reactive oxygen species and reactive nitrogen species and triggering programmed cell death. Additionally, mitochondria coordinate with other organelles to integrate and amplify diverse immune signals. In this review, we summarize recent advances in understanding how mitochondria function in plant immunity and how pathogens target mitochondria for host defense suppression.

Glutathione S-transferase interactions enhance wheat resistance to powdery mildew but not wheat stripe rust

Wheat stripe rust and powdery mildew are important worldwide diseases of wheat (Triticum aestivum). The wheat cultivar Xingmin318 (XM318) is resistant to both wheat stripe rust and powdery mildew, which are caused by Puccinia striiformis f. sp. tritici (Pst) and Blumeria graminis f. sp. tritici (Bgt), respectively. To explore the difference between wheat defense response against Pst and Bgt, quantitative proteomic analyses of XM318 inoculated with either Pst or Bgt were performed using tandem mass tags technology. A total of 741 proteins were identified as differentially accumulated proteins (DAPs). Bioinformatics analyses indicated that some functional categories, including antioxidant activity and immune system process, exhibited obvious differences between Pst and Bgt infections. Intriguingly, only 42 DAPs responded to both Pst and Bgt infections. Twelve DAPs were randomly selected for reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis, and the mRNA expression levels of 11 were consistent with their protein expression. Furthermore, gene silencing using the virus-induced gene silencing system indicated that glutathione S-transferase (TaGSTU6) has an important role in resistance to Bgt but not to Pst. TaGSTU6 interacted with the cystathionine beta-synthase (CBS) domain-containing protein (TaCBSX3) in both Pst and Bgt infections. Knockdown of TaCBSX3 expression only reduced wheat resistance to Bgt infection. Overexpression of TaGSTU6 and TaCBSX3 in Arabidopsis (Arabidopsis thaliana) promoted plant resistance to Pseudomonas syringae pv. Tomato DC3000. Our results indicate that TaGSTU6 interaction with TaCBSX3 only confers wheat resistance to Bgt, suggesting that wheat has different response mechanisms to Pst and Bgt stress.

Genome-wide association study of traits in sacred lotus uncovers MITE-associated variants underlying stamen petaloid and petal number variations

Understanding the genetic variants responsible for floral trait diversity is important for the molecular breeding of ornamental flowers. Widely used in water gardening for thousands of years, the sacred lotus exhibits a wide range of diversity in floral organs. Nevertheless, the genetic variations underlying various morphological characteristics in lotus remain largely unclear. Here, we performed a genome-wide association study of sacred lotus for 12 well-recorded ornamental traits. Given a moderate linkage disequilibrium level of 32.9 kb, we successfully identified 149 candidate genes responsible for seven flower traits and plant size variations, including many pleiotropic genes affecting multiple floral-organ-related traits, such as NnKUP2. Notably, we found a 2.75-kb presence-and-absence genomic fragment significantly associated with stamen petaloid and petal number variations, which was further confirmed by re-examining another independent population dataset with petal number records. Intriguingly, this fragment carries MITE transposons bound by siRNAs and is related to the expression differentiation of a nearby candidate gene between few-petalled and double-petalled lotuses. Overall, these genetic variations and candidate genes responsible for diverse lotus traits revealed by our GWAS highlight the role of transposon variations, particularly MITEs, in shaping floral trait diversity.

Genome-wide characterization of cys-tathionine-β-synthase domain-containing proteins in sugarcane reveals their role in defense responses under multiple stressors

Cys-tathionine-β-synthase (CBS) domain-containing proteins (CDCPs) are essential for regulating plant responses to various biotic and abiotic stressors. This study describes the systematic identification and characterization of CDCP family genes in Saccharum spontaneum. A total of 95 SsCDCP genes and eight phylogenetic groups were identified that were distributed over 29 chromosomes of the AP85-441 genome. Most (78/95) SsCDCPs underwent fragment duplication events, and 64 gene pairs were located in synteny blocks. Expression profiling of nine ShCDCPs was also carried out in the Saccharum spp. cultivars ROC22 and MT11-611 that are resistant and susceptible to red stripe, respectively, in response to: (i) Infection by the bacterial pathogen Acidovorax avenue subsp. avenae (Aaa); (ii) abiotic stressors (drought and salinity); and (iii) exogenous salicylic acid (SA) treatment. Members of one gene pair (ShCBSD-PB1-5A and ShCBSD-PB1-7A-1) with a fragment duplication event acted as negative regulators in sugarcane under four stresses, as supported by the significantly decreased expression levels of ShCBSD-PB1-5A (23-83%) and ShCBSD-PB1-7A-1 (15-75%) at all-time points, suggesting that they have functional redundancy. Genes in another pair, ShCBS-4C and ShCBS-4D-1, which have a fragment duplication event, play opposing regulatory roles in sugarcane exposed to multiple stresses, particularly Aaa and NaCl treatments. ShCBS-4C expression was significantly decreased by 32-77%, but ShCBS-4D-1 expression was dramatically upregulated by 1.2-6.2-fold in response to Aaa treatment of both cultivars across all-time points. This result suggested that both genes exhibited functional divergence. Meanwhile, the expression of SsCBSDCBS-5A was significantly upregulated in ROC22 by 1.4-4.6-fold in response to the four stressors. These findings provide important clues for further elucidating the function of ShCDCP genes in sugarcane responding to a diverse range of stresses.

Adenylates regulate Arabidopsis plastidial thioredoxin activities through the binding of a CBS domain protein

Cystathionine-β-synthase (CBS) domains are found in proteins of all living organisms and have been proposed to play a role as energy sensors regulating protein activities through their adenosyl ligand binding capacity. In plants, members of the CBSX protein family carry a stand-alone pair of CBS domains. In Arabidopsis (Arabidopsis thaliana), CBSX1 and CBSX2 are targeted to plastids where they have been proposed to regulate thioredoxins (TRXs). TRXs are ubiquitous cysteine thiol oxido-reductases involved in the redox-based regulation of numerous enzymatic activities as well as in the regeneration of thiol-dependent peroxidases. In Arabidopsis, 10 TRX isoforms have been identified in plastids and divided into five sub-types. Here, we show that CBSX2 specifically inhibits the activities of m-type TRXs toward two chloroplast TRX-related targets. By testing activation of NADP-malate dehydrogenase and reduction of 2-Cys peroxiredoxin, we found that TRXm1/2 inhibition by CBSX2 was alleviated in the presence of AMP or ATP. We also determined, by pull-down assays, a direct interaction of CBSX2 with reduced TRXm1 and m2 that was abolished in the presence of adenosyl ligands. In addition, we report that, compared with wild-type plants, the Arabidopsis T-DNA double mutant cbsx1 cbsx2 exhibits growth and chlorophyll accumulation defects in cold conditions, suggesting a function of plastidial CBSX proteins in plant stress adaptation. Together, our results show an energy-sensing regulation of plastid TRX m activities by CBSX, possibly allowing a feedback regulation of ATP homeostasis via activation of cyclic electron flow in the chloroplast, to maintain a high energy level for optimal growth.

MoBiFC: development of a modular bimolecular fluorescence complementation toolkit for the analysis of chloroplast protein-protein interactions

BACKGROUND

The bimolecular fluorescence complementation (BiFC) assay has emerged as one of the most popular methods for analysing protein-protein interactions (PPIs) in plant biology. This includes its increasing use as a tool for dissecting the molecular mechanisms of chloroplast function. However, the construction of chloroplast fusion proteins for BiFC can be difficult, and the availability and selection of appropriate controls is not trivial. Furthermore, the challenges of performing BiFC in restricted cellular compartments has not been specifically addressed.

RESULTS

Here we describe the development of a flexible modular cloning-based toolkit for BiFC (MoBiFC) and proximity labelling in the chloroplast and other cellular compartments using synthetic biology principles. We used pairs of chloroplast proteins previously shown to interact (HSP21/HSP21 and HSP21/PTAC5) and a negative control (HSP21/ΔPTAC5) to develop standardised Goldengate-compatible modules for the assembly of protein fusions with fluorescent protein (FP) fragments for BiFC expressed from a single multigenic T-DNA. Using synthetic biology principles and transient expression in Nicotiana benthamiana, we iteratively improved the approach by testing different FP fragments, promoters, reference FPs for ratiometric quantification, and cell types. A generic negative control (mCHERRY) was also tested, and modules for the identification of proximal proteins by Turbo-ID labelling were developed and validated.

CONCLUSIONS

MoBiFC facilitates the cloning process for organelle-targeted proteins, allows robust ratiometric quantification, and makes available model positive and negative controls. Development of MoBiFC underlines how Goldengate cloning approaches accelerate the development and enrichment of new toolsets, and highlights several potential pitfalls in designing BiFC experiments including the choice of FP split, negative controls, cell type, and reference FP. We discuss how MoBiFC could be further improved and extended to other compartments of the plant cell and to high throughput cloning approaches.

Genetic Conservation of CBS Domain Containing Protein Family in Oryza Species and Their Association with Abiotic Stress Responses

Crop Wild Relatives (CWRs) form a comprehensive gene pool that can answer the queries related to plant domestication, speciation, and ecological adaptation. The genus ‘Oryza’ comprises about 27 species, of which two are cultivated, while the remaining are wild. Here, we have attempted to understand the conservation and diversification of the genes encoding Cystathionine β-synthase (CBS) domain-containing proteins (CDCPs) in domesticated and CWRs of rice. Few members of CDCPs were previously identified to be stress-responsive and associated with multiple stress tolerance in rice. Through genome-wide analysis of eleven rice genomes, we identified a total of 36 genes encoding CDCPs in O. longistaminata, 38 in O. glaberrima, 39 each in O. rufipogon, O. glumaepatula, O. brachyantha, O. punctata, and O. sativa subsp. japonica, 40 each in O. barthii and O. meridionalis, 41 in O. nivara, and 42 in O. sativa subsp. indica. Gene duplication analysis as well as non-synonymous and synonymous substitutions in the duplicated gene pairs indicated that this family is shaped majorly by the negative or purifying selection pressure through the long-term evolution process. We identified the presence of two additional hetero-domains, namely TerCH and CoatomerE (specifically in O. sativa subsp. indica), which were not reported previously in plant CDCPs. The in silico expression analysis revealed some of the members to be responsive to various abiotic stresses. Furthermore, the qRT-PCR based analysis identified some members to be highly inducive specifically in salt-tolerant genotype in response to salinity. The cis-regulatory element analysis predicted the presence of numerous stress as well as a few phytohormone-responsive elements in their promoter region. The data presented in this study would be helpful in the characterization of these CDCPs from rice, particularly in relation to abiotic stress tolerance.

Functions of Redox Signaling in Pollen Development and Stress Response

Cellular redox homeostasis is crucial for normal plant growth and development. Each developmental stage of plants has a specific redox mode and is maintained by various environmental cues, oxidants, and antioxidants. Reactive oxygen species (ROS) and reactive nitrogen species are the chief oxidants in plant cells and participate in cell signal transduction and redox balance. The production and removal of oxidants are in a dynamic balance, which is necessary for plant growth. Especially during reproductive development, pollen development depends on ROS-mediated tapetal programmed cell death to provide nutrients and other essential substances. The deviation of the redox state in any period will lead to microspore abortion and pollen sterility. Meanwhile, pollens are highly sensitive to environmental stress, in particular to cell oxidative burst due to its peculiar structure and function. In this regard, plants have evolved a series of complex mechanisms to deal with redox imbalance and oxidative stress damage. This review summarizes the functions of the main redox components in different stages of pollen development, and highlights various redox protection mechanisms of pollen in response to environmental stimuli. In continuation, we also discuss the potential applications of plant growth regulators and antioxidants for improving pollen vigor and fertility in sustaining better agriculture practices.

The knowns and unknowns of intracellular partitioning of carbon and nitrogen, with focus on the organic acid-mediated interplay between mitochondrion and chloroplast

The presence of specialized cellular compartments in higher plants express an extraordinary degree of intracellular organization, which provides efficient mechanisms to avoid misbalancing of the metabolism. This offers the flexibility by which plants can quickly acclimate to fluctuating environmental conditions. For that, a fine temporal and spatial regulation of metabolic pathways is required and involves several players e.g. organic acids. In this review we discuss different facets of the organic acid metabolism within plant cells with special focus to those related to the interactions between organic acids compartmentalization and the partitioning of carbon and nitrogen. The connections between organic acids and CO₂ assimilation, tricarboxylic acid (TCA) cycle, amino acids metabolism, and redox status are highlighted. Moreover, the key enzymes and transporters as well as their function on the coordination of interorganellar metabolic exchanges are discussed.

Increased Drought Resistance 1 Mutation Increases Drought Tolerance of Upland Rice by Altering Physiological and Morphological Traits and Limiting ROS Levels

To discover new mutants conferring enhanced tolerance to drought stress, we screened a mutagenized upland rice (Oryza sativa) population (cv. IAPAR9) and identified a mutant, named idr1-1 (increased drought resistance 1-1), with obviously increased drought tolerance under upland field conditions. The idr1-1 mutant possessed a significantly enhanced ability to tolerate high-drought stresses. Map-based cloning revealed that the gene LOC_Os05g26890, residing in the mapping region of IDR1 locus, carried a single-base deletion in the idr1-1 mutant. IDR1 encodes the Gα subunit of the heterotrimeric G protein (also known as RGA1), and this protein was localized in nucleus and to plasma membrane or cell periphery. Further investigations indicated that the significantly increased drought tolerance in idr1-1 mutants stemmed from a range of physiological and morphological changes, including greater leaf potentials, increased proline contents, heightened leaf thickness and upregulation of antioxidant-synthesizing and drought-induced genes, under drought-stressed conditions. Especially, reactive oxygen species (ROS) production might be remarkably impaired, while ROS-scavenging ability appeared to be markedly enhanced due to significantly elevated expression of ROS-scavenging enzyme genes in idr1-1 mutants under drought-stressed conditions. In addition, idr1-1 mutants showed reduced expression of OsBRD1. Altogether, these results suggest that mutation of IDR1 leads to alterations in multiple layers of regulations, which ultimately leads to changes in the physiological and morphological traits and limiting of ROS levels, and thereby confers obviously increased drought tolerance to the idr1-1 mutant.

Comparative Transcriptome Analysis of Male Sterile Anthers Induced by High Temperature in Wheat (Triticum aestivum L.)

Global warming will have a negative effect on agricultural production as high temperature (HT) stress can seriously threaten plant growth and reproduction. Male sterility caused by HT may be exploited by the creation of a male-sterile line, which has great potential for application in crop heterosis. Therefore, it is important to understand the molecular mechanisms of anther abortion induced by HT in wheat, which remain unclear at present. In this study, we performed phenotype improve language in the abstract and comparative transcriptome analysis of the male sterile anthers induced by HT in wheat. Compared with Normal anthers, the cytological analysis indicated that HT-induced male sterile anthers were smaller and had no starch accumulation in pollen grains, which is consistent with the results observed by scanning electron microscopy (SEM). The 9601 differentially expressed genes (DEGs) identified by transcriptome sequencing compared with the Normal anthers were noticeably involved in the following pathways: starch and sucrose metabolism, phosphatidylinositol (PI) signaling system, peroxidase activity and response to oxidative stress, and heme binding. In addition, TUNEL assays were performed and the results further confirmed the excessive accumulation of reactive oxygen species (ROS) in sterile anthers. Moreover, a total of 38 hub genes were obtained from the protein-protein interaction network analysis of these pathways, including genes, for example, heat shock protein 90 (HSP90), thioredoxin-like protein 1, peroxidase (POD), calreticulin, UDP glucose pyrophosphorylase (UGPase), sucrose synthase, phosphatidylinositol-4-phosphate 5-Kinase (PIP5K), cytochrome c, and Cystathionine beta-synthase X6-like (CBSX6-like). These findings provide insights for predicting the functions of the candidate genes, and the comprehensive analysis of our results is helpful for studying the abortive interaction mechanism induced by HT in wheat.

Cys-SH based quantitative redox proteomics of salt induced response in sugar beet monosomic addition line M14

BACKGROUND

Salt stress is a major abiotic stress that limits plant growth, development and productivity. Studying the molecular mechanisms of salt stress tolerance may help to enhance crop productivity. Sugar beet monosomic addition line M14 exhibits tolerance to salt stress.

RESULTS

In this work, the changes in the BvM14 proteome and redox proteome induced by salt stress were analyzed using a multiplex iodoTMTRAQ double labeling quantitative proteomics approach. A total of 80 proteins were differentially expressed under salt stress. Interestingly, A total of 48 redoxed peptides were identified for 42 potential redox-regulated proteins showed differential redox change under salt stress. A large proportion of the redox proteins were involved in photosynthesis, ROS homeostasis and other pathways. For example, ribulose bisphosphate carboxylase/oxygenase activase changed in its redox state after salt treatments. In addition, three redox proteins involved in regulation of ROS homeostasis were also changed in redox states. Transcription levels of eighteen differential proteins and redox proteins were profiled. (The proteomics data generated in this study have been submitted to the ProteomeXchange and can be accessed via username: reviewer_pxd027550@ebi.ac.uk, password: q9YNM1Pe and proteomeXchange# PXD027550.) CONCLUSIONS: The results showed involvement of protein redox modifications in BvM14 salt stress response and revealed the short-term salt responsive mechanisms. The knowledge may inform marker-based breeding effort of sugar beet and other crops for stress resilience and high yield.

Mitochondrial redox systems as central hubs in plant metabolism and signaling

Plant mitochondria are indispensable for plant metabolism and are tightly integrated into cellular homeostasis. This review provides an update on the latest research concerning the organization and operation of plant mitochondrial redox systems, and how they affect cellular metabolism and signaling, plant development, and stress responses. New insights into the organization and operation of mitochondrial energy systems such as the tricarboxylic acid cycle and mitochondrial electron transport chain (mtETC) are discussed. The mtETC produces reactive oxygen and nitrogen species, which can act as signals or lead to cellular damage, and are thus efficiently removed by mitochondrial antioxidant systems, including Mn-superoxide dismutase, ascorbate-glutathione cycle, and thioredoxin-dependent peroxidases. Plant mitochondria are tightly connected with photosynthesis, photorespiration, and cytosolic metabolism, thereby providing redox-balancing. Mitochondrial proteins are targets of extensive post-translational modifications, but their functional significance and how they are added or removed remains unclear. To operate in sync with the whole cell, mitochondria can communicate their functional status via mitochondrial retrograde signaling to change nuclear gene expression, and several recent breakthroughs here are discussed. At a whole organism level, plant mitochondria thus play crucial roles from the first minutes after seed imbibition, supporting meristem activity, growth, and fertility, until senescence of darkened and aged tissue. Finally, plant mitochondria are tightly integrated with cellular and organismal responses to environmental challenges such as drought, salinity, heat, and submergence, but also threats posed by pathogens. Both the major recent advances and outstanding questions are reviewed, which may help future research efforts on plant mitochondria.