Abstract
Background:Auxin is the only plant hormone that exhibits transport polarity that is mediated by three classes of proteins, AUX/LAX influx carriers, the PIN and ABCB efflux carriers. Extensive studies have been conducted to examine the biological functions of auxin transporter genes using model plants systems and in several plant species. Despite this, information regarding the comprehensive analysis of auxin transporter genes in potato species and information regarding the expression patterns of these genes in response to external stresses remains scarce.Results: Here, we conducted a genome-wide annotation of the StLAX, StPIN, and StABCB auxin transporter gene families to examine genomic distributions, gene structures, phylogenic relationships and co-expression analysis. From these analyses, 5 StLAXs, 10 StPINs, and 22 StABCBs were identified in the potato genome and mapped to 12 chromosomes. Constructing co-expression networks revealed 18 gene modules and potato auxin transporter genes distributed in ten of them correlating to the development of various tissues. Tissue-specific expression analysis indicated that genes from the StLAX family were expressed at significantly higher levels compared to those of the other two gene families, suggesting that the StLAXs may be more important for these designated developmental stages in potato. Quantitative real-time PCR analysis indicated responsiveness of StLAXs, StPINs, and StABCBs to auxin and PATIs, implying their possible roles in mediating intercellular auxin homoeostasis and redistribution. Additionally, the differential expression levels of the StLAX, StPIN, and StABCB genes under ABA and abiotic stresses were indicative of their specific adaptive mechanisms regulating tolerance to various environmental stimuli. Promoter cis-regulatory element analyses were used to explore a large number of auxin-responsive and stress-related cis-elements within the promoters of the StLAX, StPIN, and StABCB genes that could account for their responsiveness to diverse stresses.Conclusions: In summary, we have provided comprehensive information on StLAX, StPIN, and StABCB auxin transporter gene families in potato. We are confident that our results provide a foundation for a better understanding of auxin transport in potato, as we have demonstrated the biological significance of these family genes in hormone signalling and adaption to environmental stresses.
Comprehensive Analysis and Expression Profiling of PIN, AUX/LAX, and ABCB Auxin Transporter Gene Families in Solanum tuberosum under Phytohormone Stimuli and Abiotic Stresses
