| Previous studies have shown that periods of the length of day and night is one of the important environmental factor affecting plant growth and development,although previous studies have identified some day and night cycle response gene function,but the light cycle regulation of plant growth and development of molecular mechanism is still unknown.Preliminary determination of the different photoperiod in potato leaves the transcriptome,the analysis found that differentially expressed genes(DEG)involving 121 metabolic pathways,and the experimental data analysis,identified 20 photoperiodic response upstream regulatory genes.The response illumination function of DMG400012536(St536),DMG40000663(StASR3)was unknown.And St536 is a member of the new gene family.The purpose of this study is to study the functions of these genes.The specific results are as follows:(1)Database retrieval and sequence analysis showed that the St536 gene cDNA sequence contains 648 bp ORF,encoding 215 amino acid composition,peptide formed the 91th to 110th 20 amino acid composition of the membrane structure domain;StASR3 gene cDNA sequence contains 336bp ORF,which encodes a polypeptide composed of 111 amino acids.(2)The synthesis of three genes cDNA cloning connect it to the plant eukaryotic expression vector TDNA,built too many and inhibition of expression vector of agrobacterium strain restructuring root carcinoma GV3101-pC-35S-St536+/-,GV3101-pC-35S-StASR3+/-,agrobacterium mediated root carcinoma,by transformation of recombinant strains common tobacco,get positive transformation strain screening.(3)The subcellular localization results expressed by St536 showed that St536-GFP fusion protein overlapped with the mitochondrial marker signal and combined with the presence of its transmembrane domain,indicating that St536 protein was expressed in the mitochondrial membrane.The results confirmed the prediction of mitochondrial expression of St536 homology in the genomic annotation.(4)The stomatal conductance and net photosynthetic rate of the StASR3 overexpression lines were reduced by 33%and 26%,respectively.The average ATP accumulation was increased by 57%compared with the control.The average salicylic acid accumulation was reduced by 44%compared with the control.Combined with previous studies,the results showed that increased expression of StASR3 reduced the accumulation of endogenous hormone salicylic acid in leaves,reduced stomatal conductance and redox levels,and reduced the sensitivity of leaves to ABA stress.Despite the overexpression of StASR3,the accumulation of chlorophyll and ATP increased,but the decrease in stomatal conductance led to a decrease in the rate of net photosynthesis.(5)The St536 excessive expression,relative length,leaf cellulose accumulation and porosity than in control was reduced by 20%and 17%respectively,photosynthetic rate and stomatal conductance are respectively 4.6 and 3.5 of the control,accumulation of ATP and chlorophyll increased significantly,combined with previous studies,this study suggests that St536 excessive expression,reduced to defend the leaves of cellulose accumulation,stomatal opening and closing more flexible,stomatal conductance and photosynthetic rate.(6)It is concluded that overexpression of StASR3 enhances drought tolerance due to decreased stomatal conductance due to decreased accumulation of salicylic acid.The mitochondrial membrane protein St536 is contractile to protect cell wall cellulose accumulation,enhancing stomatal conductance and photosynthetic rate.This study not only clear the StASR3 regulation salicylic acid accumulation,mitochondrial membrane protein St536 involved in cellulose accumulation,regulation of stomatal and photosynthesis,and provides the analytic signal of the two important experimental evidence.In addition,it is also clear that increasing the expression of StASR3,reduce the stomatal conductance,and define the endogenous hormones that lead to the decrease of stomatal conductance,and provide theoretical basis for further revealing how ASR genes regulate drought tolerance. |
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