評估燕麥對冠銹病的反應及其遺傳組成

Abstract

燕麥 (Avena sativa L.) 做為芻料作物，其產量對於動物飼料的供給至關重要。燕麥冠銹病是由Puccinia coronata f. sp. avenae (Pca) 所致，為使得燕麥產量減損最嚴峻的一種真菌性病害；而育成具有抗性表現的燕麥品種是目前最有效的田間防治方法。近年來於臺灣燕麥田區亦觀察到冠銹病之危害，但文獻中欠缺對臺灣燕麥冠銹病菌之認識。因此，本研究目的有三：(1) 識別來自Collaborative Oat Research Enterprise的110個代表世界栽培燕麥多樣性之燕麥品系對於臺灣本土燕麥冠銹病生理小種的感染型態與病害嚴重程度；(2) 建立影像分析系統以評估燕麥冠銹病的病害嚴重程度；(3) 以及透過全基因體關聯性分析 (Genome-wide association analysis, GWA) 評估燕麥對於臺灣本土燕麥冠銹病生理小種具有幼苗抗性和成株抗性相關之位點。本研究發展影像分析技術以評估燕麥品系對燕麥冠銹病病原菌產生的抗感病反應，利用計算孢子囊堆部位對葉面積的佔比，以取得量化的連續型外表型資料。透過影像分析所得之結果鑑別出四個具有潛在成株抗性的燕麥品系，並利用GWA探測出21個與抗病相關候選位點，多數候選位點位於1A、3A、3D、4A、4C、6C、6D、7A與7C染色體上。本研究成果提供未來燕麥抗銹病育種之候選親本、性狀評估法，及候選抗病基因座之資訊，為臺灣本土燕麥抗銹病育種奠定基礎。

Oat (Avena sativa L.), as a forage crop, its production is crucial to supply animal feed. Oat crown rust, a disease caused by Puccinia coronata f. sp. avenae (Pca), is the most serious fungal disease that reduces oat production. Developing oat varieties with plant resistance is an efficient strategy for defending the plant against this pathogen. Crown rust damages have recently been observed in oat fields in Taiwan, however, there is a lack of knowledge on the Pca in Taiwan in the literature. Therefore, the objectives of this study were (1) to characterize the infection type and disease severity on a diversity panel composed of 110 lines from the Collaborative Oat Research Enterprise; (2) to establish an image-based system to estimate the disease severity of oat crown rust; and (3) to identify seedling resistance and adult plant resistance loci to Pca appeared in Taiwan using genome-wide association analysis (GWA). Four candidate lines carrying adult plant resistance (APR) were identified based on the results from image analysis at seedling and adult plant stages. Twenty-one candidate resistant loci were identified using GWA and most of them located on the chromosomes 1A, 3A, 3D, 4A, 4C, 6C, 6D, 7A and 7C. The results of this study provided the candidate lines for oat crown rust resistance breeding, an image-based phenotyping method for disease severity estimation, and the information on candidate resistance loci, which laid the foundation for the oat crown rust resistance breeding in Taiwan.