Open Access

ARTICLE

Enhanced Ultraviolet‑B Radiation Suppresses Magnaporthe oryzae Infection and Alleviates Its Damage to the Photosynthesis of Rice Leaves

by Qinghao Zhang¹, Yijie Yang¹, Jiong Wu¹, Hongru Li¹, Yuan Li¹, Zuran Li^2,*, Yongmei He^1,*

1 College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
2 College of Horticulture and Landscape, Yunnan Agricultural University, Kunming, 650201, China

* Corresponding Authors: Zuran Li. Email: ; Yongmei He. Email:

(This article belongs to the Special Issue: Photosynthetic Responses to Biotic and Abiotic Stress)

Phyton-International Journal of Experimental Botany 2024, 93(10), 2613-2628. https://doi.org/10.32604/phyton.2024.056014

Received 12 July 2024; Accepted 11 September 2024; Issue published 30 October 2024

Abstract

In the present study, an indoor potting experiment was conducted to study the effects of enhanced UV-B radiation and Magnaporthe oryzae on the growth, stomatal structure, photosynthesis, and endogenous hormone contents of a traditional rice cultivar Baijiaolaojing in the Yuanyang terraces of Yunnan Province. In addition, the relationships between these parameters and disease indices were analyzed. We aimed to clarify the response of the photosynthetic physiology of rice under the combined stress of UV-B radiation and M. oryzae. Compared with the M. oryzae infection treatment, all the treatments, including M. oryzae infection before (MBR), simultaneously with (MSR), and after (MAR) UV-B radiation significantly increased the rice height and biomass by 4%–11% and 30%–111%, respectively, and the stomatal structure and carotenoids content of leaves, while decreasing the contents of chlorophyll a and b, by 21%–41% and 63%–73%, respectively. Both the MSR and MBR treatments significantly increased the photosynthetic rate and transpiration rate of rice leaves. The MAR treatment weakened chlorophyll fluorescence parameters, including the actual photosystem II (PS II) photochemical efficiency, electron transport rate, photochemical quenching, and nonphotochemical quenching by 40%, 39%, 43%, and 24%, respectively. Moreover, the treatments of MAR, MSR, and MBR decreased the phytohormones content and the M. oryzae disease index by 27%–62% in rice leaves. Thus, the enhanced UV-B radiation contributed to suppressing the M. oryzae infection and alleviating its damage to the photosynthesis of rice leaves. This study is valuable for the control of rice blast fungus and offers important insights into plant pathology.

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