Alleviation of norflurazon-induced photobleaching by overexpression of Fe-chelatase in transgenic rice

Joon-Heum Park; Sunyo Jung

doi:10.1584/jpestics.D21-021

Alleviation of norflurazon-induced photobleaching by overexpression of Fe-chelatase in transgenic rice

J Pestic Sci. 2021 Aug 20;46(3):258-266. doi: 10.1584/jpestics.D21-021.

Authors

Joon-Heum Park¹, Sunyo Jung¹

Affiliation

¹ School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Korea.

Abstract

We examined the effect of Bradyrhizobium japonicum FeCh (BjFeCh) expression on the regulation of porphyrin biosynthesis and resistance to norflurazon (NF)-induced photobleaching in transgenic rice. In response to NF, transgenic lines F4 and F7 showed lesser declines in chlorophyll, carotenoid, F _v/F _m, ϕ_PSII, and light-harvesting chlorophyll (Lhc) a/b-binding proteins as compared to wild-type (WT) plants, resulting in the alleviation of NF-induced photobleaching. During photobleaching, levels of heme, protoporphyrin IX (Proto IX), Mg-Proto IX (monomethylester), and protochlorophyllide decreased in WT and transgenic plants, with lesser decreases in transgenic plants. Most porphyrin biosynthetic genes were greatly downregulated in WT and transgenic plants following NF treatment, with higher transcript levels in transgenic plants. The expression of BjFeCh in transgenic rice may play a protective role in mitigating NF-induced photobleaching by maintaining levels of heme, chlorophyll intermediates, and Lhc proteins. This finding will contribute to understanding the resistance mechanism of NF-resistant crops and establishing a new strategy for weed control.

Keywords: Fe-chelatase; chlorophyll fluorescence; heme; photobleaching; porphyrin.

© Pesticide Science Society of Japan 2021. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) License (https://creativecommons.org/licenses/by-nc-nd/4.0/).