Maize Research Institute, Sichuan Agricultural University, Chengdu, 611130, China.
Institute of Qinghai-Tibetan Plateau, Southwest Minzu University, Chengdu, 610041, China.
Theor Appl Genet. 2023 Apr 24;136(5):116. doi: 10.1007/s00122-023-04362-6.
Two candidate genes (ZmbZIP113 and ZmTSAH1) controlling low-temperature germination ability were identified by QTL-seq and integrative transcriptomic analyses. The functional verification results showed that two candidate genes positively regulated the low-temperature germination ability of IB030. Low-temperature conditions cause slow maize (Zea mays L.) seed metabolism, resulting in slow seedling emergence and irregular seedling emergence, which can cause serious yield loss. Thus, improving a maize cultivar's low-temperature germination ability (LTGA) is vital for increasing yield production. Wild relatives of maize, such as Z. perennis and Tripsacum dactyloides, are strongly tolerant of cold stress and can thus be used to improve the LTGA of maize. In a previous study, the genetic bridge MTP was constructed (from maize, T. dactyloides, and Z. perennis) and used to obtain a highly LTGA maize introgression line (IB030) by backcross breeding. In this study, IB030 (Strong-LTGA) and Mo17 (Weak-LTGA) were selected as parents to construct an F offspring. Additionally, two major QTLs (qCS1-1 and qCS10-1) were mapped. Then, RNA-seq was performed using seeds of IB030 and the recurrent parent B73 treated at 10 °C for 27 days and 25 °C for 7 days, respectively, and two candidate genes (ZmbZIP113 and ZmTSAH1) controlling LTGA were located using QTL-seq and integrative transcriptomic analyses. The functional verification results showed that the two candidate genes positively regulated LTGA of IB030. Notably, homologous cloning showed that the source of variation in both candidate genes was the stable inheritance of introgressed alleles from Z. perennis. This study was thus able to analyze the LTGA mechanism of IB030 and identify resistance genes for genetic improvement in maize, and it proved that using MTP genetic bridge confers desirable traits or phenotypes of Z. perennis and tripsacum essential to maize breeding systems.
两个候选基因（ZmbZIP113 和 ZmTSAH1）通过 QTL-seq 和综合转录组分析被鉴定为控制低温萌发能力的基因。功能验证结果表明，两个候选基因正向调控 IB030 的低温萌发能力。低温条件导致玉米种子代谢缓慢，导致幼苗出土缓慢且不整齐，从而导致严重的产量损失。因此，提高玉米品种的低温萌发能力（LTGA）对于提高产量至关重要。玉米的野生近缘种，如 Z. perennis 和 Tripsacum dactyloides，对冷胁迫具有很强的耐受性，因此可用于改良玉米的 LTGA。在之前的一项研究中，构建了遗传桥梁 MTP（来自玉米、T. dactyloides 和 Z. perennis），并通过回交育种获得了具有高 LTGA 的玉米渗入系（IB030）。在这项研究中，选择 IB030（强 LTGA）和 Mo17（弱 LTGA）作为亲本构建 F1 后代。此外，定位了两个主要的 QTL（qCS1-1 和 qCS10-1）。然后，分别用 IB030 和轮回亲本 B73 的种子进行 RNA-seq 分析，分别在 10°C 下处理 27 天和 25°C 下处理 7 天，利用 QTL-seq 和综合转录组分析定位了控制 LTGA 的两个候选基因（ZmbZIP113 和 ZmTSAH1）。功能验证结果表明，两个候选基因正向调控 IB030 的 LTGA。值得注意的是，同源克隆表明，两个候选基因的变异来源是从 Z. perennis 稳定遗传的渗入等位基因。因此，本研究能够分析 IB030 的 LTGA 机制，并鉴定玉米遗传改良的抗性基因，证明利用 MTP 遗传桥梁赋予了玉米育种系统所必需的 Z. perennis 和 Tripsacum 的理想性状或表型。
