Molecular Plant最新文献

In conclusion, aligning crop development with market demands is not just a strategic move for economic stability; it is a requisite for building resilient, profitable, and sustainable agricultural systems. By doing so, the sector can provide stability for farmers and affordability for consumers and contribute to the socio-economic resilience of communities worldwide.

Plants mount induced resistance and adult-plant resistance against different pathogens throughout the whole growth period. Rice production faces threats from multiple major diseases, including rice blast, sheath blight, and bacterial leaf blight. Here, we report that the miR172a-SNB-MYB30 module regulates both induced and adult-plant resistance to these three major diseases via lignification in rice. Mechanistically, pathogen infections induce the expression of miR172a, which downregulates the transcription factor SNB to release its suppression of MYB30, leading to an increase in lignin biosynthesis and disease resistance throughout the whole growth period. Moreover, expression levels of miR172a and MYB30 gradually increase and are consistently correlated with lignin contents and disease resistance during rice development, reaching a peak at full maturity, whereas SNB RNA levels are negatively correlated with lignin contents and disease resistance, indicating the involvement of the miR172a-SNB-MYB30 module in adult-plant resistance. The functional domain of SNB protein and its binding sites in the MYB30 promoter are highly conserved among more than 4000 rice accessions, while abnormal expression of miR172a, SNB, or MYB30 compromises yield traits, suggesting artificial selection of the miR172a-SNB-MYB30 module during rice domestication. Taken together, these results reveal a novel role for a conserved miRNA-regulated module that contributes significantly to induced and adult-plant resistance against multiple pathogens by increasing lignin accumulation, deepening our understanding of broad-spectrum resistance and adult-plant resistance.

As drastic climatic changes significantly impact global agriculture, the importance of conserving and utilizing wild germplasm has gained prominance. In this context, the conservation and sustainable utilization of wild rice germplasm resources have become a high priority. Although efforts to conserve and sustainably utilize wild rice germplasm are underway globally, they are fragmented and require international cooperation to advance climate-resilient rice breeding and ensure future food securiety.

Herbivore insects deploy salivary effectors to manipulate the defense of their host plants. However, it remains unclear whether small RNAs from insects function as effectors in regulating plant-insect interactions. Here, we report that a microRNA (miR29-b) found in the saliva of phloem-feeding whitefly (Bemisa tabaci) can transfer into the host plant phloem during feeding and fine-tune the defense response of tobacco (Nicotiana tabacum). The salivary gland-enriched BtmiR29-b was produced by BtDicer 1 and released into tobacco via salivary exosomes. Once inside the plant, BtmiR29-b hijacks tobacco Argonaute 1 to silence the defense gene Bcl-2-associated athanogene 4 (NtBAG4). In tobacco, NtBAG4 acts as the positive regulator of phytohormones (salicylic acid) SA and (jasmonic acid) JA, enhancing plant defense against whitefly attacks. Interestingly, we also found that miR29-b acts as a salivary effector in another Hemipteran insect, the aphid Myzus persicae, where it also inhibits tobacco resistance by degrading NtBAG4. Moreover, miR29-b is highly conserved not only in Hemiptera, but also across other insect orders such as Coleoptera, Hymenoptera, Orthoptera, and Blattaria. Computational analysis suggests that miR29-b may target the evolutionarily conserved BAG4 gene in other plant species as well. We further provide evidence on BtmiR29-b mediated BAG4 cleavage and defense suppress in tomato (Solanum lycopersicum). Taken together, our work demonstrated an insect-conserved miR29-b effector fine-tuning plant SA/JA-mediated defense by cross-kingdom silencing of the host BAG4 gene. These findings provide new insight into the defense and counter-defense mechanisms between herbivores and their host plants.

Medicago, a member of the Leguminosae or Fabaceae family, encompasses the most significant forage crops globally, notably alfalfa (Medicago sativa L.). Its close diploid relative, Medicago truncatula, serves as an exemplary model plant for investigating leguminous growth and development, as well as its symbiosis with rhizobia. Over the past decade, advancements in Medicago genomics have significantly progressed our understanding of the molecular regulatory mechanisms underlying various traits. In this review, we comprehensively summarize the progress made in the fields of genomics research, growth and development (comprising compound leaf development, shoot branching, flowering time regulation, inflorescence development, floral organ development, and seed dormancy), resistance to abiotic and biotic stresses, symbiotic nitrogen fixation with rhizobia, as well as molecular breeding. Furthermore, we propose avenues for future research endeavors in Medicago molecular biology for the upcoming decade, highlighting those areas that have yet to be untapped or remain ambiguous.

In eukaryotic cells, autophagosomes are double-membrane vesicles that are highly mobile and traffic along cytoskeletal tracks. While core autophagy-related proteins (ATGs) and other regulators involved in autophagosome biogenesis in plants have been extensively studied, the specific components regulating plant autophagosome motility remain elusive. In this study, using TurboID-based proximity labelling, we identify the retromer subcomplex comprising sorting nexin 1 (SNX1), SNX2a, and SNX2b as interacting partners of ATG8. Remarkably, SNX proteins decorate ATG8-labeled autophagosomes and facilitate their coordinated movement along microtubules. Depletion of SNX proteins restricts the motility of autophagosomes in the cytoplasm, resulting in decreased autophagic flux. Furthermore, we show that the microtubule-associated protein CLASP serves as a bridge, connecting the SNX-ATG8-decorated autophagosomes to the microtubules. Genetically, the clasp-1 mutant phenotype resembles that of plants with disrupted SNXs or microtubule networks, displaying diminished autophagosome motility and reduced autophagic flux. Collectively, our study unveils a hitherto unanticipated role of the SNXs subcomplex in connecting autophagosomes with microtubules to promote autophagosome mobility in Arabidopsis.

Angraecum sesquipedale, also known as Darwin's orchid, possesses an exceptionally long nectar spur. Charles Darwin predicted the orchid to be pollinated by a hawkmoth with a correspondingly long proboscis, later identified as Xanthopan praedicta. In this plant-pollinator interaction, the A. sesquipedale flower emits a complex blend of scent compounds dominated by diurnally regulated oximes (R₁R₂C=N-OH) to attract crepuscular and nocturnal pollinators. The molecular mechanism of oxime biosynthesis remains unclear in orchids. Here, we present the chromosome-level genome of A. sesquipedale. The haploid genome size is 2.10 Gb and represents 19 pseudochromosomes. Cytochrome P450 encoding genes of the CYP79 family known to be involved in oxime biosynthesis in seed plants are not present in the A. sesquipedale genome nor in the genomes of other members of the orchid family. Metabolomic analysis of the A. sesquipedale flower revealed a substantial release of oximes at dusk during the blooming stage. By integrating metabolomic and transcriptomic correlation approaches, flavin-containing monooxygenases (FMOs) encoded by six tandem-repeat genes in the A. sesquipedale genome are identified as catalyzing the formation of oximes present. Further in vitro and in vivo assays confirm the function of FMOs in the oxime biosynthesis. We designate these FMOs as Orchid Oxime Synthases 1-6. The evolutionary aspects related to the CYP79 gene losses and neofunctionalization of FMO-catalyzed biosynthesis of oximes in Darwin's orchid provide new insights into the convergent evolution of biosynthetic pathways.