Exploration Of Aux/IAA Transcription Factors In Potato Roots Under Drought Stress

Affected by the earth's climate change,global agricultural land has gradually decreased,and the area of arid land is increasing.Drought has become the most severe abiotic stress factor that limits crop growth and yield increase.Potato?Solanum tuberosum L.?,as the main food crop in China,has great potential in solving the problem of food shortage and improving food safety in the future.It has a low ability to penetrate the arid soil and is considered to be a drought-sensitive crop because of its narrow root structure.The Aux/IAA transcription factor can regulate the geotropism growth of plant roots to absorb more water to improve drought tolerance,but its research on the regulation of potato root development has not been reported.In this study,the basic root tips,primary stolons and tubers in the tuber bulking stage of potato varieties"Atlantic"and"Qingshu 9"with obvious differences in drought resistance under drought stress were constructed 6 transcriptome databases by Illumina high-throughput sequencing technology.Differentially expressed Aux/IAA transcription factors in different components of the potato root system under drought stress was screened.The expression patterns of Aux/IAA transcription factors in basic root tips,primary stolons and tubers at different growth and development stages of different potato varieties under normal irrigation and drought treatment were studied using qRT-PCR technology,and key genes were tapped.The following results have been achieved:1.Through RNA-Seq technology analysis,59,234 differential genes were obtained at the transcription level.Compared with"Qingshu 9",there were 4620differentially expressed genes in the basic root tips of"Atlantic",of which 2045 genes were up-regulated and 2575 genes were down-regulated;there were 2186differentially expressed genes in primary stolons,1311 genes were up-regulated and875 genes were down-regulated;there were 4759 differentially expressed genes in tubers,of which 3175 genes were up-regulated and 1584 genes were down-regulated.2.According to GO annotation analysis of differentially expressed genes,all of the genes involved in 21 biological processes,16 cell components and 15 molecular functions.KEGG enrichment analysis showed that the differentially expressed genes were mainly enriched in 20 KEGG pathways.3.16 differential genes with high expression levels were select randomly to verify the accuracy of the RNA-seq by qRT-PCR,which are Aux/IAA25,Aux/IAA22,Auxin response factor,Aux/IAA6,Aux/IAA3,3 SAUR family proteins,Auxin response family protein,ARF transcription Factors,Aux/IAA18,Aux/IAA24,Auxin-inducible protein 6B,Jasmonic acid-amino acid binding enzyme,Auxin and ethylene react GH₃and 5,6-rosin acid.The basic root tips,primary stolons and tubers of"Atlantic"and"Qingshu 9"in the tuber bulking stage under"drought treatment"were tested.The results of this experiment showed that the correlation between gene expression and RNA-Seq sequencing results was high?r²=0.865?,indicating that the RNA-Seq results were reliable.4.6 Aux/IAA transcription factors with significant expression differences and annotations related to plant growth hormone transcriptional regulation function were selected to study the expression patterns of"Qingshu 9"and"Atlantic"under the treatments of"drought stress"and"normal irrigation".The results showed that under drought stress,Aux/IAA3,Aux/IAA6,Aux/IAA22 and Aux/IAA25 transcription factors were up-regulated in potato root tips,primary stolons and tuber tissues,and gradually increased from seedling stage to tuber bulking stage up to the highest expression level,the expression was decreased during tuber maturation stage;Aux/IAA18 and Aux/IAA24 transcription factors were down-regulated in basal root tips,primary stolons and tuber tissues,and continued to be down-regulated from seedling stage to tuber maturity stage.Compared with"Atlantic",6 transcription factors are more significant in"Qingshu 9"up or down.This study laid the foundation for further research on the function of potato root Aux/IAA transcription factors.