Low temperature is a major factor limiting rice productivity and geographical distribution. Improved cold tolerance and expanded cultivation to high-altitude or high-latitude regions would help meet growing rice demand. Here we explored a QTL for cold tolerance and cloned the gene, CTB4a (cold tolerance at booting stage), encoding a conserved leucine-rich repeat receptor-like kinase. We show that different CTB4a alleles confer distinct levels of cold tolerance and selection for variation in the CTB4a promoter region has occurred on the basis of environmental temperature. The newly generated cold-tolerant haplotype Tej-Hap-KMXBG was retained by artificial selection during temperate japonica evolution in cold habitats for low-temperature acclimation. Moreover, CTB4a interacts with AtpB, a beta subunit of ATP synthase. Upregulation of CTB4a correlates with increased ATP synthase activity, ATP content, enhanced seed setting and improved yield under cold stress conditions. These findings suggest strategies to improve cold tolerance in crop plants.
低溫是限制水稻產(chǎn)量和地域分布的主要因素。提高水稻耐冷性，擴(kuò)大高海拔或高緯度地區(qū)的種植面積，將有助于滿足日益增長(zhǎng)的水稻需求。在這里，我們探討并克隆了一個(gè)耐冷相關(guān)的QTL，該基因CTB4a（cold tolerance at booting stage，孕穗期的耐寒性），編碼一個(gè)保守的富含亮氨酸重復(fù)序列的受體樣激酶。不同的CTB4a等位基因賦予水稻不同程度的耐冷性，同時(shí)，環(huán)境溫度篩選了CTB4a啟動(dòng)子區(qū)域的變異。新產(chǎn)生的耐冷單倍型Tej-Hap-KMXBG，是溫帶粳稻在低溫環(huán)境中人為選擇的結(jié)果，以適應(yīng)低溫環(huán)境。此外，AtpB是ATP合酶的一個(gè)β亞基，CTB4a能與其互作。上調(diào)CTB4a的表達(dá)，能增加的ATP合酶活性、ATP含量，增強(qiáng)在寒冷脅迫條件下種子結(jié)實(shí)率，并提高糧食產(chǎn)量。這些結(jié)果為改善作物耐冷性提出策略。