The Gene Editing Of GW6a And GNP1 Effect On Plant Height And Yield In Rice Variety Of Huang Huazhan

The plant height is an important factor that affect crop structure,dominance of root,biomass,lodging resistance,crowding tolerance and mechanical harvesting.During the first ‘green revolution’,in order to reach the most ideal trait,semi-dwarfing traitwas utilized to maximize yield under irrigation and high fertilizer utilization by reducing lodging and increase harvest rates,Plant height traits in rice are controlled by multiple genes,which are located in a complex network.At present,more than 30 genes controlling plant height have been identified through reverse genetics and map-based cloning,among which are mainly involved in the biosynthesis or signal transduction of plant hormones.Many studies have found that gibberellins(GAs),brassinosteroids(BRs)and strigolactones(SLs)can control the plant height.Plant height is one of the important factors affecting rice structure.It also has a direct impact on plant yield,but its molecular mechanism in rice has been seldom studied.In this study,we obtained the double-gene mutants of GW6 a and GNP1 in the background of Huang Huazhan through CRISPR/Cas9.By crossing with the wild type,we obtained heterozygous double-gene mutants without vector,and after that we also obtained nine different genotypes through self-separation.Through character investigation,we found that the GW6 a and GNP1 single-gene mutants were respectively about 16.58 cm and 14.12 cm shorter than the wild-type,while the GW6 a and GNP1 double-gene mutants was twice shorter than the single-gene mutants,with an average of 33.87 cm.In addition to the shorter plant height,other agronomic traits of the double-gene mutants have also changed,such as shorter panicle length and lower yield.However,the 1000-grain weight of double-gene mutants increased.Through real-time fluorescence quantitative PCR,we discovered that the GW6 a and GNP1 genes in the apical of rice stems at the heading stage had very low expression levels in the mutants.Which is synchronized to the genes of Os GA20ox2,Os GA2ox3 and RGL3 related to gibberellin signaling.Experiments have shown that mutations of the two genes GW6 a and GNP1 cause reduction in the plant height,panicle length and rice yield by reducing the content of gibberellin in plants.The rice variety of Huang huazhan has reached an ideal architecture.It is worthy of exploring that whether other lodging varieties can improve lodging resistance and increase field harvest by knocking out these two genes.Discovering more plant height genes,studying the plant height mechanism,and supplementing the plant height network,provides ideal genetic resources for producing semi-dwarf rice phenotypes.It also provides effective strategy for selection and breeding the lodging resistance and high-yield rice varieties.