Genome-wide identification of rubber tree PILS auxin transporter gene families and functional characterization of HbPILS6.

Artículo

Given the pivotal role of PILS genes in regulating auxin homeostasis and stress responses, this study thoroughly investigated the genomic characteristics of the rubber tree PIN-LIKES (PILS) gene family and their roles in plant growth and stress adaptation. Through screening, a total of 13 HbPILS genes were identified and classified into two subfamilies. These genes exhibit structural and sequence diversity among subfamilies but maintain conservation within them. Promoter analysis showed cis-elements related to stress response and hormone regulation, suggesting their function in plant environmental adaptation. Notably, HbPILS6 was significantly upregulated in the dwarf mutant of rubber tree, indicating its importance in growth control. qRT-PCR analysis showed that HbPILS6 expression significantly changed under various stress conditions, implying its role in integrating auxin-mediated growth regulation and stress response. Transgenic Arabidopsis thaliana overexpressing HbPILS6 exhibited phenotypes such as dwarfism, slender stems, and reduced lignification, along with changes in the expression of genes related to auxin synthesis and signaling pathways, further confirming the function of HbPILS6. Subcellular localization analysis confirmed the presence of HbPILS6 on the plasma membrane, providing evidence for its involvement in auxin efflux and signal transduction. This study not only filled the genomic information gap of the rubber tree HbPILS gene family but also provided new insights into the role of HbPILS6 in plant growth and stress adaptation, offering a theoretical basis and potential target genes for the genetic improvement and stress resistance enhancement of rubber tree.