REVEALING THE DYNAMICS OF F-ACTIN IN TOMATO POLLEN TUBE AND ITS RESPONSE TO TEMPERATURE AND ROS BIOLOGY.

In angiosperms, the pollen tube plays a pivotal role for delivering male gametes from the pollen grain to the female gametophyte within the ovule. This crucial transport system ensures successful fertilization and the subsequent formation of seeds and fruits. The actin cytoskeleton plays a vital role in elongating pollen tubes. It provides structural support, guides the direction of pollen tube tip growth, and facilitates the elongation of the pollen tube for successful fertilization. While the role of F-actin has been extensively studied in model plant species, relatively little is known about how F-actin dynamics regulate pollen tube growth in agricultural crops like tomato. Our previous findings also indicate that elevated temperatures significantly reduced pollen tube growth in tomato while increasing the frequency of pollen tube tip bursting. Plants generate increased levels of ROS in response to high temperatures as a part of their stress response mechanisms and preliminary data showed higher accumulation of ROS in the pollen tube. Therefore, I hypothesize that that elevated levels of ROS due to high temperature treatment may have a significant impact on F-actin dynamics and pollen tube growth.This project aims to understand F-actin dynamics in tomato pollen tubes by utilizing genetically encoded constructs to visualize F-actin in real-time live-cell imaging. I will concurrently explore the potential effects of elevated temperatures on F-actin dynamics while quantifying pollen tube growth. I will also generate ROS and F-actin double reporter lines to test the hypothesis that altered ROS homeostasis influence F-actin dynamics in the tomato pollen tube. This project seeks to investigate the impact of elevated temperature on pollen tube F-actin dynamics, with a specific focus on unraveling the molecular and cellular mechanisms through which ROS influences F-actin dynamics during heat stress. The result will enhance our understanding of how ROS could impact the structural and functional characteristics of F-actin in response to temperature stress throughout the pollen tube development.This project has 3 specific aims:Aim 1: Imaging actin dynamics during tomato pollen tube growth in wild-type and a mutant with impaired pollen germination and tube growth.Aim 2: Examining the effect of elevated temperature on the dynamics of F-actin during tomato pollen tube growth and how this effect be reversed by drugs that modulate actin dynamics.Aim 3: Determination of whether elevated ROS as a result of elevated temperature alters F-actin dynamics.