Molecular Plant最新文献

Heat stress poses a significant threat to grain yield. Our previous study identified TT1, which encodes an α2 subunit of the 26S proteasome, as a critical regulator for rice heat tolerance, representing the first cloned QTL for crop heat tolerance. However, the mechanisms mediated by TT1 still remained elusive. In this study, we unveil SUMO-conjugating enzyme 1 (SCE1), which interacts with TT1 and acts as a downstream component of TT1, engaging in the TT1-mediated 26S proteasome degradation. SCE1 functions as a negative regulator of heat tolerance and can be linked to ubiquitination modification. Additionally, we observed that sHSPs such as Hsp24.1 and Hsp40 can undergo SUMOylation mediated by SCE1, leading to increased accumulation of sHSPs in the absence of SCE1. Furthermore, we propose that the global SUMOylation modulated by SCE1 serves as a crucial signal in response to heat stress, and the rapid decline in elevated SUMOylation is considered a positive effect to enhance heat tolerance due to the loss of SCE1 gene function. Reducing protein levels of SCE1 significantly enhanced grain yield under high-temperature stress by improving seed-setting rate and rice grain filling capacity. Our results uncover the critical role of SCE1 in TT1-mediated heat tolerance pathway, regulating the abundance of sHSP proteins and SUMOylation, and ultimately impacting rice heat tolerance. These findings underscore the significant potential of the TT1-SCE1 module in improving the heat tolerance of crops.

Aromatic rice is globally favored for its distinctive scent, not only increasing nutritional value but also enhancing economic importance. However, apart from 2-acetyl-1-pyrroline (2-AP), the metabolic basis of aroma remains elusive, and the genetic underlying of the accumulation of fragrance metabolites are largely unknown. Here, we revealed 2-AP and fatty acid-derived volatile metabolites (FAVs) as key contributors to rice aroma by combining aroma rating with molecular docking. Using volatilome-based GWAS, we identified two regulatory genes that determine the natural variation of these fragrance metabolites. We demonstrated that OsWRKY19 not only enhances fragrance by negatively regulating OsBADH2 but also promotes agricultural traits in rice. Additionally, we revealed OsNAC021 that negatively regulates FAVs through the LOX pathway, and the knockout of it resulted in the over-accumulation of grain FAVs without a yield penalty. Our findings provide a compelling example of deciphering the genetic regulatory mechanisms underlying rice fragrance and pave the way for the creation of aromatic rice varieties.

As well as being a popular vegetable crop worldwide, waxy corn represents an important amylopectin source. However, little is known about the breeding history and flavor characteristics of this crop. In this study, comparative-omic analyses between 318 diverse waxy corn and 507 representative field corn inbred lines revealed that many metabolic pathways and genes exhibited characteristics of selection during the breeding history of waxy corn, contributing to the divergence between waxy and field corn. We show that waxy corn is not only altered in its glutinous property, but that sweetness, aroma, and palatability are all significantly affected. A substantial proportion (43%) of flavor-related metabolites have pleiotropic effects, impacting both flavor and yield characteristics and 27% of these metabolites are related to antagonistic outcomes on yield and flavor. Furthermore, we demonstrated, through multiple concrete examples, how yield and quality are coordinately or antagonistically regulated at the genetic level. In particular, we identified some sweet molecules such as DIMBOA and raffinose, that do not participate in the starch biosynthesis pathway, as potential targets for breeding a new type of "sweet-waxy" corn. Our findings shed light on the historical selection of waxy corn and demonstrate the genetic and metabolic basis of waxy corn flavor, thereby collectively providing valuable resources and knowledge for future crop breeding for improved nutritional quality.

Short summary: The WA-type CMS in rice is widely used in Asia for its stability and adaptability. Li Li's team found that the Rf20 gene enhances the fertility restoration of Rf4. It is recommended to introduce the H3 haplotype of the Rf20 gene into indica or Basmati rice, and high-temperature fertility issues in CMS-WA can be addressed through Rf20 gene editing.

The Lamiaceae family is renowned for its terpenoid-based medicinal components, but Leonurus, which has traditional medicinal uses, stands out for its alkaloid-rich composition. Leonurine, the principal active compound found in Leonurus, has demonstrated promising effects in reducing blood lipids and treating strokes. However, the biosynthetic pathway of leonurine remains largely unexplored. Here, we present the chromosome-level genome sequence assemblies of Leonurus japonicus, known for its high leonurine production, and Leonurus sibiricus, characterized by very limited leonurine production. By integrating genomics, RNA sequencing, metabolomics, and enzyme activity assay data, we constructed the leonurine biosynthesis pathway and identified the arginine decarboxylase (ADC), uridine diphosphate glucosyltransferase (UGT), and serine carboxypeptidase-like (SCPL) acyltransferase enzymes that catalyze key reactions in this pathway. Further analyses revealed that the UGT-SCPL gene cluster evolved by gene duplication in the ancestor of Leonurus and neofunctionalization of SCPL in L. japonicus, which contributed to the accumulation of leonurine specifically in L. japonicus. Collectively, our comprehensive study illuminates leonurine biosynthesis and its evolution in Leonurus.

Plants can synthesize a wide range of terpenoids in response to various environmental cues. However, the specific regulatory mechanisms governing terpenoid biosynthesis at the cellular level remain largely elusive. In this study, we employed single-cell RNA sequencing to comprehensively characterize the transcriptome profile of cotton leaves and established a hierarchical transcriptional network regulating cell-specific terpenoid production. We observed substantial expression levels of genes associated with the biosynthesis of both volatile terpenes (such as β-caryophyllene and β-myrcene) and non-volatile gossypol-type terpenoids in secretory glandular cells. Moreover, two novel transcription factors, namely GoHSFA4a and GoNAC42, are identified to function downstream of the Gossypium PIGMENT GLAND FORMATION genes. Both transcription factors could directly regulate the expression of terpenoid biosynthetic genes in secretory glandular cells in response to developmental and environmental stimuli. For convenient retrieval of the single-cell RNA sequencing data generated in this study, we developed a user-friendly web server . Our findings not only offer valuable insights into the precise regulation of terpenoid biosynthesis genes in cotton leaves but also provide potential targets for cotton breeding endeavors.