Cold stress is a major factor limiting production and geographic distribution of rice (Oryza sativa). Although the growth range of japonica subspecies has expanded northward compared to modern wild rice (O. rufipogon), the molecular basis of the adaptation remains unclear. Here we report bZIP73, a bZIP transcription factor-coding gene with only one functional polymorphism (+511 G>A) between the two subspecies japonica and indica, may have facilitated japonica adaptation to cold climates. We show the japonica version of bZIP73 (bZIP73Jap) interacts with bZIP71 and modulates ABA levels and ROS homeostasis. Evolutionary and population genetic analyses suggest bZIP73 has undergone balancing selection; the bZIP73Jap allele has firstly selected from standing variations in wild rice and likely facilitated cold climate adaptation during initial japonica domestication, while the indica allele bZIP73Ind was subsequently selected for reasons that remain unclear. Our findings reveal early selection of bZIP73Jap may have facilitated climate adaptation of primitive rice germplasms.
冷脅迫是限制水稻產(chǎn)量和地理分布的主要因素。盡管粳亞種相比現(xiàn)代野生稻已經(jīng)向北擴(kuò)展，但其適應(yīng)機(jī)制仍然不清楚。本文，我們報(bào)道了一個(gè)bZIP轉(zhuǎn)錄因子編碼基因bZIP73，在粳和秈兩個(gè)亞種間僅有一個(gè)有功能的單核苷酸多態(tài)性(+511 G>A)，可能有助于粳稻適應(yīng)冷環(huán)境。我們發(fā)現(xiàn)粳型bZIP73與bZIP71互作，調(diào)節(jié)脫落酸水平和活性氧平衡。進(jìn)化和群體遺傳學(xué)分析表明BZIP33已經(jīng)經(jīng)歷了平衡選擇，在最初的粳稻馴化中，bZIP73Jap等位基因首先從野生稻的直立變異中得到選擇，并可能有助于冷脅迫適應(yīng)。而隨后秈稻等位基因bZIP73Ind因什么原因被選中尚不清楚。我們的發(fā)現(xiàn)揭示了bZIP73Jap的早期選擇促進(jìn)了原始水稻種質(zhì)的氣候適應(yīng)。