Study On Drought Resistance Of Rice Heterotrimer G Protein γ Subunit

Heterotrimeric G protein is a kind of protein that exists widely in eukaryotes and can be combined with GTP/GDP.It is an important signal protein and participates in many signal response processes.important role in the process.Rice G protein consists of an α subunit RGA1,a β subunit RGB1 and five γ subunits RGG1,RGG2,GGC2,GS3,qPE9-1.Rice G proteins have been shown to have important functions in regulating rice grain shape,growth and development,stress response and hormone response.However,the biological function of the γ subunit member RGG2 has not been studied in detail.In this study,we investigated the function of the rice G protein y subunit RGG2 in drought resistance and regulation of plant height.The main results are as follows:1.The RGG2 gene was overexpressed in NIP.Compared with the wild type NIP,the overexpressed line was significantly dwarfed,and the plant height was shorter than wild type in each growth period.The grains of the overexpressed line became smaller,and the grain length and width of the overexpressed lines were significantly smaller than those of the wild type.At the same time,the leaf angle of first and second leaves of the overexpressed line was significantly larger than that of the wild type.2.Under drought and PEG treatments,the leaves of the wild type showed obvious yellowing and curling,and the overexpression lines were not obvious.The survival rates of the overexpression lines were significantly higher than those of the wild type.The stomatal conductance and transpiration rate of the overexpression lines were significantly lower than those of the wild type,and they had stronger water retention capacity.The detection of oxidative indicators showed that the overexpression lines suffered less oxidative stress than the wild type.3.The results of detection of ABA contents in leaves showed that the ABA contents of the overexpression lines were higher than those of the wild type.The ability of the overexpression line to synthesize ABA was stronger than that of the wild type,and the overexpression line was more sensitive to ABA concentration.The expression of 9 genes related to ABA synthesis and response was detected by fluorescence quantitative detection.The results showed that in the overexpression lines,the expression levels of these genes were higher than those of the wild type after drought treatment.4.The results of RNA-seq analysis showed that more differential genes were enriched in GO pathways related to oxidative stress.At the same time,it was also found that more differential genes were enriched in the GO pathway relatd to metal ion transport.5.We found that RGG2 may interact with catalase(CAT)by mass spectrometry screening of CoIP and Pull down.Pull down by prokaryotic expression of the two proteins verified that RGG2 interacts with CAT in the intracellular environment,but not in vitro.In conclusion,we believe that RGG2 enhances rice oxidative stress tolerance and enhances rice drought tolerance by affecting hormone synthesis,providing a new strategy for rice drought resistance.