Macquarie University
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Identifying stress tolerance genes in plants from distantly related crop relatives

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posted on 2023-07-21, 03:57 authored by Farhad Masoomi-Aladizgeh

Heat stress leads to male germ line (pollen) sterility, and consequently, failure to produce seeds and fruits, yet little is known about why developing pollen is so vulnerable at the molecular level. My PhD aims to identify molecular mechanisms behind the heat sensitivity of male cell lines. I have exposed different stages of pollen development, both in commercial and an Australian wild Gossypium, to moderate and extreme heat to investigate the molecular response to heat. Using physiological experiments and -omics approaches, I have found that tetrad formation (circa meiosis) in commercial cotton is the most vulnerable stage of pollen development to heat. The sensitivity of tetrads in the commercial cotton is most likely due to impaired mRNA splicing machinery, translation of non-essential genes and enhanced level of protein transport, compared with the later stages of development and vegetative tissues. Importantly, the findings in the wild cotton demonstrated different molecular responses of pollen to high temperature, which might contribute to its thermotolerance. The identified genes and pathways from the wild cotton pollen allows us to speculate on mechanisms of thermotolerance in male reproductive cell lines. These findings provide insights for future studies that will eventually lead to development of new cultivars for hotter environments.


Table of Contents

Chapter 1: Introduction -- Chapter 2: Materials and methods -- Chapter 3: Pollen development in cotton (Gossypium hirsutum) is highly sensitive to heat exposure during the tetrad stage -- Chapter 4: Patterns of gene expression in pollen of cotton (Gossypium hirsutum) indicate down-regulation as a feature of thermotolerance -- Chapter 5: Genome survey sequencing of wild cotton (Gossypium robinsonii) reveals insights into proteomic responses of pollen to extreme heat -- Chapter 6: Genetic relatedness and evolutionary history across Australian ecotypes of Themeda triandra (kangaroo grass) -- Chapter 7: Conclusion and future directions -- Appendix

Awarding Institution

Macquarie University

Degree Type

Thesis PhD

Department, Centre or School

School of Natural Sciences

Year of Award


Principal Supervisor

Brian Atwell

Additional Supervisor 1

Paul Haynes


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130 pages

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