Studies On The Biological Function Of TaVTE3 And TaRKL1 In Wheat(Triticum Aestivum L.)

Tocopherol has been widely studied in recent years as an important fat-soluble redox buffer in plants.As a key enzyme in the synthesis of tocopherol,α-tocopherol has the highest activity,and its gene function in wheat has not been reported.Therefore in this study,common wheat lines xiaoyan 101 was used as the test lines,barley stripe Mosaic virus induced gene silencing system（BSMV-VIGS）was adopted,and the function of Ta VTE3 was further studied by an allelic lines.The results showed that compared with BSMV:γ00 plants,the BSMV:Ta VTE3 plants:（1）CO₂ assimilation rate,stomatal conductance,transpiration rate and water use efficiency were significantly reduced;（2）The maximum photochemical efficiency and photosynthetic performance index of wheat decreased,while the heat dissipation increased;（3）Increasing non-photochemical quenching decreased the electron transfer rate;（4）More sensitive to photooxidation after high light treatment;（5）The protein expression levels of D1 and Rubisco were significantly decreased;（6）The contents of chlorophyll and carotenoids were significantly lower than the control plants;（7）The total antioxidant capacity was decreased,which was manifested in the significantly decreased ascorbic acid content and the decreased ascorbic acid peroxidase activity;（8）The maximum root length became shorter.In addition,similar results were observed in the mutant lines"T",compared with the common lines"C":（1）Ta VTE3 gene was highly expressed in the leaves;（2）There was no significant difference in PQ content;（3）The maximum root length and total root number decrease and the root becomes thinner;（4）Plant height decreased,panicle became shorter,spike number of 666.7 m^-2,thousand-kernel weight decreased;（5）The grain width decreases,the grain is more slender;（6）Wheat yield decreased by 12.02%（Beijing）and 7.35%（Zhaoxian）.So,the Ta VTE3 gene affects the photosynthetic capacity and the antioxidant capacity of wheat,and the Ta VTE3 gene may also affect the root development and finally affect its yield.Receptor-like kinases play crucial roles in regulation of plant growth,development,and responses to environmental stimuli.In this study,an uncharacterized Ta RKL1encoding a receptor-like cytoplasmic kinase was investigated in Triticum aestivum cv.Xiaoyan 101 using barley stripe mosaic virus induced gene silencing system（BSMV-VIGS）.The results showed that compared with the BSMV:γ00 plants（control）,the BSMV:Ta RKL1 plants:（1）The CO₂ assimilation rate,stomatal conductance,and transpiration rate were significantly lower;（2）The maximum photochemical efficiency and electron transport flux decreased while the dissipated energy flux enhanced;（3）The content of chlorophylls and carotenoids was significantly;（4）The H₂O₂ content was significantly higher,which resulted from lower ascorbate peroxidase activity;（5）Ta Psb A,Ta Psb R,Ta Psa N,Ta CHLH,and Ta DVR were down-regulated,and the transcripts of Ta Fe SOD,Ta Mn SOD,Ta Cu/Zn SOD,Ta APX,and Ta MDAR also declined,senescence associated genes（Ta SAG1,Ta SAG4,Ta SAG6,and Ta SAG12）were repressed while only Ta SAG7 was induced,four abscisic acid biosynthesis genes（Ta ABA1,Ta ABA4,Ta NCED4,Ta ABA2）were down-regulated while Ta BCH1 and Ta AAO3 did not alter significantly.Collectively,this study for the first time showed that Ta RKL1 regulates photosynthesis and H₂O₂ homeostasis.It may be a potential target gene for wheat radiance use efficiency improvement in the future.