Lu Guangwen, Wu Fu-Qing, Wu Weixun, Wang Hong-Jun, Zheng Xiao-Ming, Zhang Yunhui, Chen Xiuling, Zhou Kunneng, Jin Mingna, Cheng Zhijun, Li Xueyong, Jiang Ling, Wang Haiyang, Wan Jianmin
National Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
Plant J. 2014 May;78(3):468-80. doi: 10.1111/tpj.12487. Epub 2014 Apr 11.
Low temperature (LT) is one of the most prevalent factors limiting the productivity and geographical distribution of rice (Oryza sativa L.). Although significant progress has been made in elucidating the effect of LT on seed germination and reproductive development in rice, the genetic component affecting vegetative growth under LT remains poorly understood. Here, we report that rice cultivars harboring the dominant LTG1 (Low Temperature Growth 1) allele are more tolerant to LT (15-25°C, a temperature range prevalent in high-altitude, temperate zones and high-latitude areas), than those with the ltg1 allele. Using a map-based cloning strategy, we show that LTG1 encodes a casein kinase I. A functional nucleotide polymorphism was identified in the coding region of LTG1, causing a single amino acid substitution (I357K) that is associated with the growth rate, heading date and yield of rice plants grown at LT. We present evidence that LTG1 affects rice growth at LT via an auxin-dependent process(es). Furthermore, phylogenetic analysis of this locus suggests that the ltg1 haplotype arose before the domestication of rice in tropical climates. Together, our data demonstrate that LTG1 plays an important role in the adaptive growth and fitness of rice cultivars under conditions of low ambient temperature.
低温是限制水稻（Oryza sativa L.）生产力和地理分布的最普遍因素之一。尽管在阐明低温对水稻种子萌发和生殖发育的影响方面已取得显著进展，但影响低温下营养生长的遗传成分仍知之甚少。在此，我们报告，携带显性等位基因LTG1（低温生长1）的水稻品种比携带ltg1等位基因的品种更耐低温（15 - 25°C，这是高海拔、温带和高纬度地区普遍存在的温度范围）。使用基于图谱的克隆策略，我们表明LTG1编码一种酪蛋白激酶I。在LTG1的编码区鉴定到一个功能性核苷酸多态性，导致单个氨基酸替换（I357K），这与低温下生长的水稻植株的生长速率、抽穗期和产量相关。我们提供证据表明LTG1通过生长素依赖的过程影响低温下的水稻生长。此外，该位点的系统发育分析表明ltg1单倍型出现在热带气候下水稻驯化之前。总之，我们的数据表明LTG1在环境低温条件下对水稻品种的适应性生长和适应性方面发挥重要作用。
