Licheng Liu1,2,3, Xiaoxiang Li2,3, Sanxiong Liu2,3, Jun Min2,3, Wenqiang Liu2,3, Xiaowu Pan2,3, Baohua Fang2,3, Min Hu2,3, Zhongqi Liu1, Yongchao Li4,5, Haiqing Zhang6. 1. College of Agriculture, Hunan Agricultural University, Changsha, 410128, China. 2. Hunan Rice Research Institute, Hunan Academy of Agricultural Science, Changsha, 410125, China. 3. MOA Key Laboratory of Indica Rice Genetics and Breeding in the Middle and Lower Reaches of Yangtze River Valley, Changsha, 410125, China. 4. Hunan Rice Research Institute, Hunan Academy of Agricultural Science, Changsha, 410125, China. yongchao_li128@163.com. 5. MOA Key Laboratory of Indica Rice Genetics and Breeding in the Middle and Lower Reaches of Yangtze River Valley, Changsha, 410125, China. yongchao_li128@163.com. 6. College of Agriculture, Hunan Agricultural University, Changsha, 410128, China. hunanhongli@aliyun.com.
Abstract
BACKGROUND: Rice (Oryza sativa L.) is an important crop and a staple food for half of the population around the world. The recent water and labor shortages are encouraging farmers to shift from traditional transplanting to direct-seeding. However, poor germination and slow elongation of the coleoptile constrains large-scale application of direct-seeding. OBJECTIVE: This study was aimed to investigate the genetic basis of the anaerobic germination (AG) potential using a set of Oryza nivara (O. nivara) introgression lines (ILs). METHODS: In this study, a total of 131 ILs were developed by introducing O. nivara chromosome segments into the elite indica rice variety 93-11 through advanced backcrossing and repeated selfing. A high-density genetic map has been previously constructed with 1,070 bin-markers. The seeds of ILs were germinated and used to measure coleoptile length under normal and anaerobic conditions. QTLs associated with AG potential were determined in rice. RESULTS: Based on the high-density genetic map of the IL population, two QTLs, qAGP1 and qAGP3 associated with AG tolerance were characterized and located on chromosomes 1 and 3, respectively. Each QTL explained 15% of the phenotypic variance. Specifically, the O. nivara-derived chromosome segments of the two QTLs were positively tolerance to anaerobic condition by increasing coleoptile length. In a further analysis of public transcriptome data, a total of 26 and 36 genes within qAGP1 and qAGP3 were transcriptionally induced by anaerobic stress, respectively. CONCLUSIONS: Utilization of O. nivara-derived alleles at qAGP1 and qAGP3 can potentially enhance tolerance to anaerobic stress at the germination stage in rice, thereby accelerating breeding of rice varieties to be more adaptative for direct-seeding.
BACKGROUND: Rice (Oryza sativa L.) is an important crop and a staple food for half of the population around the world. The recent water and labor shortages are encouraging farmers to shift from traditional transplanting to direct-seeding. However, poor germination and slow elongation of the coleoptile constrains large-scale application of direct-seeding. OBJECTIVE: This study was aimed to investigate the genetic basis of the anaerobic germination (AG) potential using a set of Oryza nivara (O. nivara) introgression lines (ILs). METHODS: In this study, a total of 131 ILs were developed by introducing O. nivara chromosome segments into the elite indica rice variety 93-11 through advanced backcrossing and repeated selfing. A high-density genetic map has been previously constructed with 1,070 bin-markers. The seeds of ILs were germinated and used to measure coleoptile length under normal and anaerobic conditions. QTLs associated with AG potential were determined in rice. RESULTS: Based on the high-density genetic map of the IL population, two QTLs, qAGP1 and qAGP3 associated with AG tolerance were characterized and located on chromosomes 1 and 3, respectively. Each QTL explained 15% of the phenotypic variance. Specifically, the O. nivara-derived chromosome segments of the two QTLs were positively tolerance to anaerobic condition by increasing coleoptile length. In a further analysis of public transcriptome data, a total of 26 and 36 genes within qAGP1 and qAGP3 were transcriptionally induced by anaerobic stress, respectively. CONCLUSIONS: Utilization of O. nivara-derived alleles at qAGP1 and qAGP3 can potentially enhance tolerance to anaerobic stress at the germination stage in rice, thereby accelerating breeding of rice varieties to be more adaptative for direct-seeding.
Authors: Tobias Kretzschmar; Margaret Anne F Pelayo; Kurniawan R Trijatmiko; Lourd Franz M Gabunada; Rejbana Alam; Rosario Jimenez; Merlyn S Mendioro; Inez H Slamet-Loedin; Nese Sreenivasulu; Julia Bailey-Serres; Abdelbagi M Ismail; David J Mackill; Endang M Septiningsih Journal: Nat Plants Date: 2015-08-24 Impact factor: 15.793