My research interests include studying auxin transport and cell polarity determination. Within my current cell model, i.e., cotton fibers, we elaborate how auxin is established for promoting cell initiation. In this model, auxin efflux carrier PIN3a is the core component for auxin gradient establishment in cotton ovule epidermis. PIN3a polarly localizes at the plasma membrane of nonfiber cells to mediate auxin transport in ovule epidermis and disappears in fiber cells for intracellular auxin accumulation. Based on these findings, we develop bioengineering strategies to improve cotton fiber yield and quality simultaneously. As cotton fibers are discrete epidermal cells in the ovule surface, it is attractive to uncover how fiber cell-enriched auxin maxima are established. My current research focuses on regulation of PIN3a localization and degradation.