查看更多>>摘要：Aromatic rice is globally favored for its distinctive scent,which not only increases its nutritional value but also enhances its economic importance.However,apart from 2-acetyl-1-pyrroline(2-AP),the metabolic basis of aroma remains to be clarified,and the genetic basis of the accumulation of fragrance metabolites is largely unknown.In this study,we revealed 2-AP and fatty acid-derived volatiles(FAVs)as key contributors to rice aroma by combining aroma rating with molecular docking.Using a volatilome-based genome-wide associ-ation study,we identified two regulatory genes that determine the natural variation of these fragrance metab-olites.Genetic and molecular analyses showed that OsWRKY19 not only enhances fragrance by negatively regulating OsBADH2 but also improves agricultural traits in rice.Furthermore,we revealed that OsNAC021 negatively regulates FAV contents via the lipoxygenase pathway,and its knockout resulted in over-accumu-lation of grain FAVs without a yield penalty.Collectively,our study not only identifies two key regulators of rice aroma but also provides a compelling example about how to deciphering the genetic regulatory mechanisms that underlie rice fragrance,thereby paving the way for the creation of aromatic rice varieties.
查看更多>>摘要：As well as being a popular vegetable crop worldwide,waxy corn represents an important amylopectin source,but little is known about its breeding history and flavor characteristics.In this study,through comparative-omic analyses between 318 diverse waxy corn and 507 representative field corn inbred lines we revealed that many metabolic pathways and genes exhibited selection characteristics during the breeding history of waxy corn,contributing to the divergence between waxy and field corn.We showed that waxy corn is not only altered in its glutinous property but also its sweetness,aroma,and palatability are all significantly affected.A substantial proportion(43％)of flavor-related metabolites have pleiotropic effects,affecting both flavor and yield characteristics,and 27％of these metabolites are related to antag-onistic outcomes on yield and flavor.Furthermore,through multiple concrete examples,we demonstrated how yield and quality are coordinately or antagonistically regulated at the genetic level.In particular,some sweet molecules,such as DIMBOA and raffinose,which do not participate in the starch biosynthesis pathway,were identified as potential targets for breeding a new type of"sweet-waxy"corn.Taken together,our findings shed light on the historical selection of waxy corn and demonstrate the genetic and metabolic basis of waxy corn flavor,collectively providing valuable resources and knowledge for future crop breeding for improved nutritional quality.
查看更多>>摘要：Heat stress poses a significant threat to grain yield.As an α2 subunit of the 26S proteasome,TT1 has been shown to act as a critical regulator of rice heat tolerance.However,the heat tolerance mechanisms medi-ated by TT1 remain elusive.In this study,we unveiled that small ubiquitin-like modifier(SUMO)-conjugating enzyme 1(SCE1),which interacts with TT1 and acts as a downstream component of TT1,is engaged in TT1-mediated 26S proteasome degradation.We showed that SCE1 functions as a negative regulator of heat tolerance in rice,which is associated with its ubiquitination modification.Furthermore,we observed that small heat-shock proteins(sHSPs)such as Hsp24.1 and Hsp40 can undergo SUMOylation mediated by SCE1,leading to increased accumulation of sHSPs in the absence of SCE1.Reducing protein levels of SCE1 significantly enhanced grain yield under high-temperature stress by improving seed-setting rate and rice grain filling capacity.Taken together,these results uncover the critical role of SCE1 in the TT1-mediated heat tolerance pathway by regulating the abundance of sHSPs and SUMOylation,and ultimately modulating rice heat tolerance.These findings underscore the great potential of the TT1-SCE1 module in improving the heat tolerance of crops.
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