Journal of Experimental Botany最新文献

Soybean is one of the primary sources of vegetable oil and protein worldwide. However, its yield improvement has lagged behind the other major crops. This study explored the potential of the sunflower transcription factor HaHB11 to enhance soybean yield and heat stress tolerance. We generated transgenic soybean plants expressing HaHB11 and evaluated their performance across four field trials. The HaHB11 plants showed a significant increase in grain number per plant compared to controls, which can be related to an increased number of nodes and pods per plant. Flowering dynamics analysis revealed delayed blooming and an increased number of flowers per node, leading to a higher pod set, particularly between nodes four and six. Principal component analysis across field trials identified temperature as a crucial factor influencing grain number, enhancing the differences exhibited by HaHB11 plants. The pollen from transgenic plants germinated better, and tubes were longer than controls under heat stress. Carbohydrate distribution analyses indicated differential allocation of nutrients, which could support the increased pod and grain set in HaHB11 plants. Additionally, vegetation indices can distinguish HaHB11 plants from controls in several developmental stages. These results indicated that HaHB11 enhances soybean yield under heat stress, becoming a promising technology for soybean improvement.

Tight regulation of messenger RNA (mRNA) stability is essential to ensure accurate gene expression in response to developmental and environmental cues. mRNA stability is controlled by mRNA decay pathways, which have traditionally been proposed to occur independently of translation. However, the recent discovery of a co-translational mRNA decay pathway (also known as CTRD) reveals that mRNA translation and decay can be coupled. While being translated, a mRNA can be targeted for degradation. This pathway was first described in yeast and rapidly identified in several plant species. This review explores recent advances in our understanding of CTRD in plants, emphasizing its regulation and its importance for development and stress response. The different metrics used to assess CTRD activity are also presented. Furthermore, this review outlines future directions to explore the importance of mRNA decay in maintaining mRNA homeostasis in plants.

Wheat is the major staple food in the human diet but its production under current climate scenarios is problematic, giving the predicted extent of land salinization and the fact that wheat is highly sensitive to soil salinity. This work aims to critically assess previous breeding efforts and pros- and cons- of targeting SOS1 and HKT1 genes to improve salinity stress tolerance in wheat. We argue that overexpressing SOS1 genes encoding Na+/H+ exchangers for Na+ removal from root to the rhizosphere may come with a caveat of increased loading of Na+ into the xylem and its delivery to the shoot, as well as numerous pleiotropic effects. Similarly, targeting HKT1 transporters for removing Na+ from the shoot comes with significant yield penalties due to the high carbon cost for osmotic adjustment; this strategy is also limited by the relatively small capacity of the root to store excessive Na+ without experiencing toxicity symptoms. We suggest that targeting tissue tolerance traits such as K+ retention in mesophyll and vacuolar Na+ sequestration in the shoot will be able to deliver better outcomes. We also call for a better understanding of the structure-function relationships of various isoforms for key genes involved in maintenance of Na+ and K+ homeostasis and a need for more in-depth physiological studies of wheat species with DD genome; a key contributor to tissue tolerance traits. Our arguments are supported by the bioinformatic analysis of the number of orthologs for some key gene between hexaploidy (AABBDD) and tetraploid (AABB) wheats and their structural differences.

Photoperiod, the length of daylight within a 24-hour cycle, serves as the most consistent signal for seasonal changes. Plants have developed mechanisms to adapt to these cycles, displaying well-established photoperiodic responses in traits like flowering time. The desynchronization of flowering time from photoperiod has been a pivotal factor in the global expansion of several major crops consumed today. This review provides an overview of current insights into how plants perceive photoperiod signals at the molecular level, how these signals interact with the circadian clock, and how they drive global responses, particularly through variations in flowering time. Furthermore, the review compiles known mutations that have influenced photoperiodism in crops and explores their contributions to agricultural expansion worldwide. Finally, it highlights physiological effects of photoperiodism mutations beyond flowering time, offering insights in the potential drawbacks of developing crops with improved photoperiodic adaptability.

MicroRNAs (miRNAs) were initially detected as approximately 20-22 nt sequences in plants. For decades miRNA-mediated regulation of target gene expression was characterized in many cases. The sequences of miR159/319 family miRNAs are conserved among land plants. The roles of miR159/319 have been comprehensively characterized in development of dicot and monocot plants. However, its biological function in bryophytes remain enigmatic. A model bryophyte Marchantia polymorpha also encodes miR319 at two loci and expresses the miRNA. We used a CRISPR/Cas9 system to edit genome sequences at MpMIR319a and/or MpMIR319b loci. The mutant lines developed relatively few gemma cups and gemmae, suggesting that MpmiR319 targets MpRKD or MpR2R3-MYB21 transcripts and suppresses its expression. We constructed miR319-resistant MpRKD (mMpRKD) and MpR2R3-MYB21 (mMpR2R3-MYB21) by decreasing the complementarity to miR319. Introduction of mMpRKD resulted in gemma/gemma cup-less liverwort mutants, but mMpR2R3-MYB21 did not. Transcription-fusion constructs between MpRKD promoter andβglucuronidase showed the gene is expressed in the rim and bottom of gemma cups. We found that the mir319a/mir319b double mutant could form gemma cups but of different sizes in a unpredictable arrangement when planted on vermiculite. These results together suggest that miR319 guides the formation of gemma cups/gemmae in standard positions collaborating with MpRKD.

The potato immune receptor Gpa2 confers host-specific resistance to the cyst nematode Globodera pallida. When transiently expressed in Nicotiana benthamiana it triggers cell death upon recognition of the matching effector GpRBP-1. Effector-triggered immunity by Gpa2 depends on the host factor RanGAP2, which is known to regulate the nucleocytoplasmic distribution and functioning of the highly homologous potato immune receptor Rx1. However, the subcellular localisation of Gpa2 and the role of RanGAP2 in determining the subcellular localisation of Gpa2 is yet unknown. Moreover, cellular mechanisms underlying nematode effector detection by Gpa2 and subsequent cell death activation remain unknown. Here, we co-expressed Gpa2 fused to nuclear localisation signals and its matching effector GpRBP-1 as a model to address these questions. We show that both the nuclear and cytoplasmic pool of Gpa2 contribute to effector-triggered cell death which depends on complex formation with RanGAP2 as a cytoplasmic retention and stabilising factor. However, using nuclear and cytoplasmic targeting signals, we demonstrate that GpRBP-1 detection by Gpa2 occurs specifically in the cytoplasm. From these data, a picture emerges in which RanGAP2 retains Gpa2 in the cytoplasm to form a pre-activation complex, which aids in GpRBP-1 detection and the activation of immune responses in a compartment-specific manner.

DNA methylation plays important roles in gene expression, transposable element silencing, and genome stability. Altering DNA methylation could generate additional phenotypic variation for crop breeding, however the lethality of epigenetic mutants in crop species has hindered its investigation. Here, we exploit partial redundancy between homoeologues in polyploid wheat to generate viable mutants in the DNA methyltransferase 1-1 (MET1-1) gene with altered methylation profiles. In Triticum turgidum (tetraploid wheat) and Triticum aestivum (hexaploid wheat), we found under-representation of higher order mutants (5/6 and 6/6 mutant met1-1 copies in hexaploid wheat and 3/4 and 4/4 copies in tetraploid wheat) when genotyping segregating seeds and seedlings, due to reduced transmission of null mutant gametes from the paternal and maternal side. The loss of four or more functional copies of MET1-1 results in decreased CG methylation in hexaploid wheat. Changes to gene expression increase stepwise with the number of mutant alleles, suggesting a dosage-dependent effect. We identified heritable changes to flowering and awn phenotypes which segregate independently of MET1-1. Together our results demonstrate that polyploidy can be leveraged to generate quantitative changes to CG methylation without the lethal consequences observed in other crops.

Aspartic proteases (APs) are extensively distributed across plant species and are integral to various developmental and defense mechanisms. This review initially examines the classification, biochemical properties, and advancements in the understanding of the subcellular localization of plant aspartic proteases. Subsequently, it delves into the diverse functions of aspartic proteases in plant vegetative and reproductive development, as well as their roles in responding to abiotic and biotic stresses. Additionally, the review addresses the specific functions of aspartic proteases in particular plant species, such as carnivorous plants and leguminous plants involved in nitrogen fixation. Collectively, this synthesis provides a comprehensive overview of the current knowledge regarding the roles of aspartic proteases in plants.

Modern agriculture faces increasing challenges from climate change and a rapidly growing global population, necessitating innovative strategies to ensure food security. Wheat wild relatives (WWR) represent a valuable genetic resource for improving wheat resilience and productivity. These species possess traits that confer resistance to pests and diseases, tolerance to environmental stresses such as drought and salinity, and enhanced nutritional quality. Recent advances in genomic sequencing and gene editing have facilitated the transfer of these beneficial traits into cultivated wheat. This review explores the potential of WWR in overcoming the limitations of current wheat varieties and enhancing climate resilience. Key topics include the genetic diversity and adaptability of WWR to harsh environments, recent breakthroughs in cross-breeding and genomics, and the emerging field of de novo domestication. Case studies showcase successful applications of wild wheat traits in modern agriculture. Harnessing WWR's genetic resources presents a viable pathway to developing high-yielding, resilient crops that sustain future food supplies. Achieving this goal requires significant investment, interdisciplinary collaboration, and robust support for research, (pre-)breeding programs, and field trials.