摘要:玉米的叶形结构与其抗旱性紧密相关，挖掘不同水分环境下调控玉米叶形相关性状的显著关联分子标记位点，可为揭示玉米叶形结构的分子遗传机理、克隆相关调控基因并进行抗旱理想株型育种提供参考。本研究在不同水分环境下分析187份玉米自交系叶长、叶宽、叶夹角、叶向值、叶面积、叶形系数及叶片卷曲度等7个叶形相关性状的变化，采用SSR标记对这些材料进行全基因组扫描并分析其遗传多样性，采用一般线性模型（GLM）寻找不同水分环境下与玉米7个叶形相关性状关联的分子标记。结果表明：1）干旱环境下187份玉米自交系的叶长、叶宽、叶夹角、叶面积均显著降低，而叶向值、叶形系数及叶片卷曲度均明显升高，且干旱环境下这7个叶形相关性状的变异比率为30.53%~198.31%。2）145对SSR标记共检测出652个等位变异，变异范围在2~13个；多态性信息量（PIC）变异范围为0.201~0.966，平均0.478。采用UPGMA聚类及群体遗传结构分析均将供试材料分为旅大红骨（LRC）、唐四平头（TSPT）、兰卡斯特（Lan）、P及瑞德（Reid）等5大类群。3）采用GLM模型，在不同水分环境下共检测到15个SSR标记与玉米的7个叶形相关性状在P < 0.01水平下关联，各标记对表型的解释率为2.25%~27.30%，72.97%的标记可在干旱环境下被检测到；其中umc1124、umc2363、umc2214、umc1742、phi331888、umc1378、bnlg1863、umc2134和umc1345标记同时与不同水分环境下的多个叶形相关性状连锁，表现出明显的“一因多效”现象。这些研究结果将为玉米叶形结构的遗传改良及抗旱理想株型分子标记辅助选择育种提供参考。
关键词:玉米/
叶形结构/
干旱/
遗传结构/
关联分析
Abstract:The leaf morphology of maize (Zea mays) is closely related to its drought resistance. The molecular markers correlated with leaf morphology traits under different watering regimes may provide insights into the genetic mechanisms and identify the breeding varieties. In this study, changes in the leaf length (LL), leaf width (LW), leaf angle (LA), leaf orientation value (LOV), leaf size (LS), leaf shape coefficient (LSC), and leaf rolling index (LRI) of 187 maize inbred lines were analyzed under different watering regimes. A genome-wide scan and the genetic diversity were analyzed with simple-sequence repeat (SSR) markers, and the associations between the markers and the leaf morphological traits were assessed via a general linear model (GLM). The results showed that:1) the coefficients of variation for the leaf morphological traits of the 187 inbred lines were 13.21%-59.23% and 9.62%-28.22% under normal water and dry conditions, respectively, indicating abundant genetic variation. There were significant differences in the seven leaf morphological traits, so the leaf morphology was adjusted by the hereditary character of the inbred line. LL, LW, LA, and LS decreased significantly under drought stress, whereas LOV, LSC, and LRI increased, and the variance rate of the seven traits was 30.53%-198.31%. 2) A total of 652 alleles were detected using 145 SSR markers. The polymorphism information content (PIC) ranged from 0.201 to 0.966, with an average of 0.478. The tested materials were divided into five groups based on unweighted pair group method with arithmetic mean clustering and population structure; the Luda red cob group, Tangsipingtou group, Lancaster group, P group, and Reid group. 3) A total of 15 SSR markers were associated with seven leaf morphologies under different watering regimes (GLM, P < 0.01), and the amount of explained phenotypic variance was 2.25%-27.30%. Approximately 72.97% of the SSR markers were detected under drought conditions. The umc1124, umc2363, umc1742, phi331888, umc1378, bnlg1863, umc2134, and umc1345 markers were simultaneously associated with multiple leaf morphologies under different watering regimes, indicating pleiotropy. These results provide useful information for the genetic improvement of leaf morphology and marker-assisted selection breeding programs for maize drought resistance and optimization.
Key words:Maize/
Leaf morphology/
Drought/
Genetic structure/
Association analysis
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