OsPPG encodes a pseudouridine-5'-phosphate glycosidase and regulates rice spikelet development

Florets are the basic structural units of spikelets,and their morphogenesis determines the yield and quality of rice grains.However,whether and how pseudouridine-5’-phosphate glycosidase participates in rice spikelet development remains an open question.In this study,we identified a novel gene,OsPPG,which encodes a peroxisome-localized pseudouridine-5’-phosphate glycosidase and regulates the development of rice spikelets.osppg mutants exhibited abnormal sterile lemma,lemma,palea,lodicule,stamens,and pistils;male sterility;shorter panicles;and reduced plant height.OsPPG was found to regulate several OsMADS genes,thereby affecting the morphogenesis of rice spikelets.Furthermore,metabolomics revealed that the OsPPG gene was involved in the decomposition of pseudouridine via the pyrimidine metabolism pathway and may affect the jasmonic acid signaling pathway.These results suggest that OsPPG is a key regulator of rice spikelet development.

Identification of natural allelic variation in TTL1 controlling thermotolerance and grain size by a rice super pan-genome∞

Continuously increasing global temperatures present great challenges to food security.Grain size,one of the critical components determining grain yield in rice(Oryza sativa L.),is a prime target for genetic breeding.Thus,there is an immediate need for genetic improvement in rice to maintain grain yield under heat stress.However,quantitative trait loci(QTLs)endowing heat stress tolerance and grain size in rice are extremely rare.Here,we identified a novel negative regulator with pleiotropic effects,Thermo‐Tolerance and grain Length 1(TTL1),from the super pan‐genomic and transcriptomic data.Loss‐of‐function mutations in TTL1 enhanced heat tolerance,and caused an increase in grain size by coordinating cell expansion and proliferation.TTL1 was shown to function as a transcriptional regulator and localized to the nucleus and cell membrane.Furthermore,haplotype analysis showed that hapL and hapS of TTL1 were obviously correlated with variations of thermotolerance and grain size in a core collection of cultivars.Genome evolution analysis of available rice germplasms suggested that TTL1 was selected during domestication of the indica and japonica rice subspecies,but still had much breeding potential for increasing grain length and thermotolerance.These findings provide insights into TTL1 as a novel potential target for the development of high‐yield and thermotolerant rice varieties.