Elucidating iron deficiency signaling in Arabidopsis thaliana

• Main Authors: Sakthivel Kailasam, 薩克錫佛
• Other Authors: Kuo-Chen Yeh
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/9mu9ag

博士 === 國立中興大學 === 生物科技學研究所 === 106 === Iron (Fe), one of the most fundamental elements for all living organisms, is required for various basic cellular functions such as respiration, photosynthesis and integral part of many enzymes. Iron deficiency anemia (IDA) has a substantial impact on human health. Nearly three billion people are affected by the IDA. To eliminate Fe-anemia from the society, crop improvement toward fortification of Fe has great significance. Enhancing Fe levels in plants is therefore useful, however, itself need an adequate knowledge on Fe homeostasis in plants. With this focus, by using chemical biology and genetic approaches, we identified new players that involve in regulation of responses to Fe deficiency in the model plant Arabidopsis thaliana. In chemical genetics approach, three small molecules (named as R3, R6 and R7) modulating Fe homeostasis were identified. The small molecule R7 was characterized in-depth whereas the effects of R3 and R6 were partially studied. Small-molecule treatment caused severe Fe-dependent chlorosis and attenuated the starvation response under Fe limited condition. By using the small molecule R7, we were able to dissect the molecular connection between nitric oxide and the Fe starvation response. Whereas R3 and R6 use helped to selectively inhibit the transcriptional network. In the EMS based mutant screening, we identified a mutant non-response to Fe-deficiency 1-1 (nrf1-1). Fe starvation response was compromised in nrf1-1. Mapping of nrf1-1 revealed a missense mutation in a methyl transferase gene, AT3G13440. Further analyses on mutant and complementation lines indicated that functional NRF1 is required for proper molecular and physiological responses to Fe-starvation. Taken together, the signaling that operate under Fe starvation has been elucidated in this research.