Department of Molecular Biology and Biotechnology, College of Science, Sheffield University, Sheffield, TN, United Kingdom.
Rice Biotechnology Lab., Rice Research & Training Center (RRTC), Field Crops Research Institute, ARC, Sakhah, Egypt.
PLoS One. 2022 Mar 29;17(3):e0266087. doi: 10.1371/journal.pone.0266087. eCollection 2022.
Rice cultivation in Egypt is limited by the scarcity of water resources. The main strategy of rice breeders to overcome this problem is to develop new high-yielding varieties that are tolerant to drought stress. In this study, an drought-tolerant (IR60080-46A) variety was crossed with commercial Egyptian varieties using the back-cross method and marker-assisted selection (MAS) approach. The advanced lines of these crosses were selected under drought stress conditions. The best-performing candidate line, RBL-112, and its parental genotypes, were evaluated under drought stress and control conditions. The RBL-112 line showed superior its root system, which in turn produced higher grain yield under drought-stress conditions than its parental and check genotypes. Furthermore, physiological and biochemical studies showed that the RBL-112 line maintained higher relative water content (RWC), maximum quantum efficiency of photosystem II (Fv/Fm) values, proline content, superoxide dismutase (SOD) activity, and lower malondialdehyde (MDA) content compared to its parents and the check. The functional expression profiles of 22 drought tolerance-related genes were studied, out of which the genes OsAHL1, OsLEA3, OsCATA, OsP5CS, OsSNAC1, Os1g64660, OsRab21, OsAPX2, OsDREB2A, OsSKIPa, and OsLG3 were strongly induced in the newly developed RBL-112 line under drought-stress conditions. It could be concluded that the new line has a higher capacity to modulate physiological activities and expression levels of several drought-induced genes to withstand drought stress with high yielding ability. This finding suggests that the RBL-112 line presents a promising new addition to enable sustainable rice cultivation under water-limited conditions, and confirms the efficiency of the approach implemented in the current study.
埃及的水稻种植受到水资源短缺的限制。水稻育种者克服这个问题的主要策略是开发新的耐旱高产品种。在这项研究中，通过回交法和标记辅助选择（MAS）方法，将耐旱品种（IR60080-46A）与商业埃及品种杂交。在干旱胁迫条件下选择这些杂交的衍生系。选择表现最好的候选系 RBL-112 及其亲本基因型，在干旱胁迫和对照条件下进行评估。RBL-112 系表现出优越的根系，这反过来又使其在干旱胁迫条件下的籽粒产量高于其亲本和对照基因型。此外，生理生化研究表明，与亲本和对照相比，RBL-112 系保持较高的相对含水量（RWC）、最大光化学量子效率（Fv/Fm）值、脯氨酸含量、超氧化物歧化酶（SOD）活性和较低的丙二醛（MDA）含量。研究了 22 个与耐旱性相关的基因的功能表达谱，其中 OsAHL1、OsLEA3、OsCATA、OsP5CS、OsSNAC1、Os1g64660、OsRab21、OsAPX2、OsDREB2A、OsSKIPa 和 OsLG3 等基因在新开发的 RBL-112 系在干旱胁迫下强烈诱导。可以得出结论，新系具有更高的能力来调节几种干旱诱导基因的生理活性和表达水平，以在高产量能力下耐受干旱胁迫。这一发现表明，RBL-112 系为在水资源有限的条件下实现可持续水稻种植提供了一个有前途的新途径，并证实了本研究中采用的方法的效率。
