Study On The Function Of StBIN2 In Regulating Seed Potato Vigor

Potato（Solanum tuberosum L.）is an important food crop in China,with abundant nutrition,high yield,and wide adaptability.Seed tuber vitality refers to the strength of the internal physiological activity of seed tubers,which is influenced by internal metabolism and environmental conditions.During the evolution process of long-term adaptation to the environment,the vitality of seed tubers during the occurrence stage,maturity stage,dormancy stage,and germination stage forms a weak strong weak strong periodic change pattern.Under the annual production model in Sichuan,the regulation of seed potato vitality plays an important role in yield.The research team identified the only negative regulatory factor StBIN2 for brassinolide（BR）signal transduction in the early stage,which has the function of delaying germination and is one of the key genes regulating seed potato vitality.However,the mechanism by which it regulates seed potato vitality is unknown.To further investigate the effect of StBIN2 on the vitality of potato seed tubers,this study conducted phenotypic statistics on the overexpression of StBIN2 during the tubering,dormancy,and germination stages of potatoes.At the same time,BR,ABA hormone signal transduction,sucrose starch synthase activity were analyzed,and related gene expression levels were measured and protein interaction（yeast two hybrid system,Y2H）experiments were conducted to explore the abscisic acid signal during the process of changes in potato seed tuber vitality caused by StBIN2 The regulatory role of key pathways such as glucose metabolism.The comprehensive morphological,physiological,and molecular level research results have preliminarily revealed the functional mechanism of StBIN2 affecting the vitality of potato seed tubers.The main research findings are as follows:1.The effect of StBIN2 on the vitality formation of seed potatoes during the formation periodThe formation period of seed potato tubers is one of the key periods for vitality formation.StBIN2 can significantly increase the number of tubers per plant in both the original and original species.Overexpression of StBIN2 can increase the number of tubers per plant by up to 76%（original species）and 69%（original species）,respectively;StBIN2also significantly increased the individual plant weight of the original seed and the original seed.Overexpression of StBIN2 can increase the individual plant weight by up to 49%（original seed）and 40%（original seed）,and the increasing trend of different plant lines is consistent with the expression trend of StBIN2.This indicates that StBIN2 has a promoting effect on the vitality of seed potatoes during this process.2.The influence mechanism of StBIN2 on the vitality formation of seed potatoes during the formation periodThe interaction between StBIN2 and ABA signaling factors St ABI1,St ABI5,St Sn RK2.2,and St PP2C promotes the downstream transmission of some ABA signals（ABI5）;Simultaneously,by promoting the enzyme activity and synthesis gene expression of sugar transport proteins St SWEET11 and St SUT,as well as promoting the expression of sucrose and starch synthesis genes St SPS and St AGPase.Clarified the impact of StBIN2 on the conversion and utilization of key substances such as glucose,sucrose,and starch during the process of tuberization,thereby providing a material basis and energy preparation for tuberization;In addition,StBIN2 also promotes the expression of tuber forming factors St SP6A and St S6K through the ABA signaling pathway,promoting tuber formation.3.Effect of StBIN2 on Dormancy and Sprouting Stage of Seed PotatoesIt has been clarified that StBIN2 has the function of delaying potato sprouting,promoting lateral growth of sprouts,making sprouts robust,and effectively avoiding sprout overgrowth;After treatment with BIN2 inhibitor Bikinin,the vitality index of potato seed tubers decreased and the buds became slender.The improvement of seed potato vitality during dormancy and sprouting is not consistent.During dormancy,especially during the transition from dormancy to sprouting,overexpression of potato sprouts is inhibited,resulting in a decrease in seed potato vitality.However,after 20 days of bud growth,the seed potato vitality index increases by 25%,and the seed potato vitality is significantly improved.4.Effect mechanism of StBIN2 on dormancy and germination period of seed potatoesDuring dormancy,the expression of StBIN2 and its kinase activity increase with the transition from dormancy to sprouting,which also confirms its important role in the initiation of sprouting,and the overexpression peak appears later.BIN2 interacts with ABA signaling factors St ABI1,St ABI5,St Sn RK2.2,and St PP2C during late dormancy,promoting the downstream pathway of ABA,inhibiting SOD and CAT activity,increasing POD activity,thereby inhibiting the synthesis and decomposition of ROS（O₂^-,H₂O₂）in the bud,and delaying germination.Upregulation of the enzyme activity and synthesis gene expression of sucrose and starch synthesis genes St SPS,St AGPase,and sucrose transport proteins St SWEET11 and St SUT during germination and subsequent bud growth provides material and energy preparation for lateral bud growth.In summary,the regulatory effect of StBIN2 on the vitality of seed potatoes changes over time,by promoting the ABA signaling pathway,which in turn upregulates genes related to tuber formation and promotes tuber formation;Simultaneously promoting the synthesis of sucrose and starch,providing material and energy preparation for tuber formation,and improving the vitality of seed potatoes.Then promote ABA,inhibit BR signaling pathway,delay ROS accumulation,inhibit sprouting and shoot elongation growth,and reduce seed potato vitality;Subsequently,it promotes sucrose synthesis,transportation,lateral growth of buds,and enhances seed potato vitality.The results of this experiment enrich the research on the mechanism of StBIN2 regulating the vitality of potato seed tubers,providing a theoretical basis for improving the vitality of potato seed tubers,guiding the annual production of potato seed tuber supply,and achieving high and stable yields.