Identification, expression profile of soybean PIN-Like (PILS) gene family and its function in symbiotic nitrogen fixation in root nodules
摘要
<p id="C3">Plant hormone auxin plays a vital role in the growth and development of plants. Auxin homeostasis and concentration gradient establishment control the polar formation of almost all organs. The synthesis, transportation, perception, and metabolic degradation of auxin in specific cells establish a concentration gradient of auxin in accordance with organ development. In legumes, roots interact with soil microorganisms to form a special organ called nodules, which is used for biological nitrogen fixation. However, the function of auxin homeostasis control of biological nitrogen fixation is unknown. Studies showed that PIN-Like (PILS) proteins in<italic> Arabidopsis</italic> helped to regulate intracellular auxin homeostasis and mediate auxin signal transmission in the downstream nucleus. In this study, 19 PILS family genes (<italic>GmPILSs</italic>) were identified in soybean genome and distributed unevenly on 10 chromosomes of soybean. <italic>GmPILSs</italic> exhibited a variety of expression patterns in nine tissue parts of soybean, and had obvious specificity of tissue expression. <italic>GmPILS1e</italic> and <italic>GmPILS1f</italic> were enriched and expressed in the rhizobia region, and the expression of <italic>GmPILS1e</italic> and <italic>GmPILS1f</italic> in nodules was down-regulated by artificial microRNA interference (amiRNAi), resulting in the increase of nitrogenase activity in the nodules. However, the overexpression of <italic>GmPILS1f</italic> leaded to the decrease nitrogenase activity in root nodules, <italic>GmPILS1e</italic> and <italic>GmPILS1f</italic> might participate in the regulation of soybean nitrogenase activity. These results lay the foundation for further analysis of the function and mechanism of soybean <italic>GmPILS</italic> family genes, and also provide valuable genetic resources for the application of nodulation and nitrogen fixation in agricultural breeding.