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.

Rice sl-MH-1 mutant induces cell death and confers blast resistance via the synergistic roles of signaling systems

Serotonin is ubiquitous across all forms of life and functions in responses to biotic and abiotic stresses.In rice,the conversion of tryptamine to serotonin is catalyzed by Sekiguchi lesion(SL).Previous studies have identified an sl mutation(a null mutation of SL)in several rice varieties and confirmed its increase of resistance and cell death.However,a systematic understanding of the reprogrammed cellular processes causing cell death and resistance is lacking.We performed a multi-omics analysis to clarify the fundamental mechanisms at the protein,gene transcript,and metabolite levels.We found that cell death and Magnaporthe oryzae(M.oryzae)infection of the sl-MH-1 mutant activated plant hormone signal transduction involving salicylic acid(SA),jasmonic acid(JA),and abscisic acid(ABA)in multiple regulatory layers.We characterized the dynamic changes of several key hormone levels during disease progression and under the cell death conditions and showed that SA and JA positively regulated rice cell death and disease resistance.SL-overexpressing lines confirmed that the sl-MH-1 mutant positively regulated rice resistance to M.oryzae.Our studies shed light on cell death and facilitate further mechanistic dissection of programmed cell death in rice.

iTRAQ-based protein profiling and functional identification of four genes involved in rice basal resistance against Magnaporthe oryzae in two contrasting rice genotypes

Rice blast,caused by Magnaporthe oryzae,is one of the most destructive rice diseases.Developing blast-resistant rice cultivars represents the most economical and environmentally friend strategy for managing the disease.In our previous study,an isobaric tags for relative and absolute quantitation(iTRAQ)-based comparative protein quantification was carried out to investigate the resistance gene Piz-t gene-mediated resistance response to infection in two contrasting rice genotypes of the Piz-t transgenic Nipponbare line(NPB-Piz-t)and its wild-type Nipponbare(NPB).Here,from the comparisons of differentially expressed proteins(DEPs)of NPB-Piz-t to the avirulent isolate KJ201(KJ201-Piz-t)and the virulent isolate RB22(RB22-Piz-t)with mock-treated NPB-Piz-t(Mock-Piz-t),NPB to the virulent isolate KJ201(KJ201-NPB)and RB22(RB22-NPB)with mock-treated NPB(Mock-NPB),1,1,and 6 common DEPs were,respectively,identified at 24,48 and 72 h post-inoculation(hpi)in the susceptible comparisons of RB22-Pizt/Mock-Piz-t,KJ201-NPB/Mock-NPB,and RB22-NPB/Mock-NPB,involving in gi|54,290,836 and gi|59,800,021 were identified in the resistance comparison KJ201-Piz-t/Mock-Piz-t at 48 and 72 hpi respectively.Moreover,four genes of Os01g0138900(gi|54,290,836),Os04g0659300(gi|59,800,021),Os09g0315700(gi|125,563,186)or Os04g0394200(gi|21,740,743)were knocked out or overexpressed in NPB using gene over-expression and CRISPR/Cas9 technology,and results verified that the Os01g0138900 obviously affected the rice blast resistance.Further,expression and targeted metabolomics analysis illuminated the resistance response of cysteine-containing substances as gi|59,800,021 under blast infection.These results provide new targets for basal resistance gene identification and open avenues for developing novel rice blast resistant materials.