Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
GM Crops Food. 2021 Jan 2;12(1):435-448. doi: 10.1080/21645698.2021.1977068. Epub 2021 Dec 22.
The ultraviolet B (UVB) sensitivity of rice cultivated in Asia and Africa varies greatly, with African rice cultivars ( Steud. and A. Chev.) being more sensitive to UVB because of their low cyclobutane pyrimidine dimer (CPD) photolyase activity, which is a CPD repair enzyme, relative to Asian rice cultivars ( L.). Hence, the production of UVB-resistant African rice with augmented CPD photolyase activity is of great importance, although difficulty in transforming the African rice cultivars to this end has been reported. Here, we successfully produced overexpressing transgenic African rice with higher CPD photolyase activity by modifying media conditions for callus induction and regeneration using the parental line (PL), UVB-sensitive African rice TOG12380 (). The overexpressing transgenic African rice carried a single copy of the CPD photolyase enzyme, with a 4.4-fold higher level of CPD photolyase transcripts and 2.6-fold higher activity than its PL counterpart. When the plants were grown for 21 days in a growth chamber under visible radiation or with supplementary various UVB radiation, the overexpressing transgenic plants have a significantly increased UVB resistance index compared to PL plants. These results strongly suggest that CPD photolyase remains an essential factor for tolerating UVB radiation stress in African rice. As a result, African rice cultivars with overexpressed CPD photolyase may survive better in tropical areas more prone to UVB radiation stress, including Africa. Collectively, our results provide strong evidence that CPD photolyase is a useful biotechnological tool for reducing UVB-induced growth inhibition in African rice crops of .
亚洲和非洲种植的水稻对紫外线 B (UVB) 的敏感度差异很大，非洲水稻品种（ Steud. 和 A. Chev.）由于其环丁烷嘧啶二聚体 (CPD) 光解酶活性较低，对 UVB 更为敏感，而 CPD 光解酶是一种 CPD 修复酶，与亚洲水稻品种（ L.）相比。因此，生产具有增强的 CPD 光解酶活性的抗 UVB 非洲水稻非常重要，尽管已经报道了将非洲水稻品种转化为这种水稻的困难。在这里，我们通过修改愈伤组织诱导和再生的培养基条件，成功地利用亲本系（PL）、对 UVB 敏感的非洲水稻 TOG12380（）生产出具有更高 CPD 光解酶活性的过表达转基因非洲水稻。过表达的转基因非洲水稻携带单个 CPD 光解酶酶，CPD 光解酶转录物水平提高了 4.4 倍，活性提高了 2.6 倍，高于其 PL 对应物。当这些植物在生长室中在可见光下或补充各种 UVB 辐射下生长 21 天时，与 PL 植物相比，过表达的转基因植物的 UVB 抗性指数显著增加。这些结果强烈表明，CPD 光解酶仍然是非洲水稻耐受 UVB 辐射胁迫的一个重要因素。因此，过表达 CPD 光解酶的非洲水稻品种可能在更易受到 UVB 辐射胁迫的热带地区，包括非洲，更好地生存。总的来说，我们的结果提供了强有力的证据，证明 CPD 光解酶是减少非洲水稻作物中 UVB 诱导的生长抑制的有用生物技术工具。
