Physiologic and molecular responses of indica–japonica subspecies tetraploid rice seed germination to ion beams

Abstract

Ionizing radiation can not only reduce the yield of rice but also cause rice toxicity, and consumption of this kind of rice threatens human health. Moreover, the production and application of freon has further caused a hole in the earth’s ozone layer, increasing the amount of ionizing radiation from the sun affecting rice. To select and breed new radiation-resistant rice varieties, dry seeds of the indica–japonica subspecies of tetraploid rice subjected to different doses of ionizing radiation were investigated for their responses during germination. The results showed that the relative water absorption, seed vigour and GA3 content sharply decreased in response to three different doses of ionizing radiation, and the regulation of the expression of genes related to α-amylase synthesis and gibberellin metabolism was disrupted. Moreover, the degree of inhibition increased with increasing dose. Notably, under 3.0 × 1017 ions/cm2 radiation, an upregulation of OsGA3ox2 expression resulted in a sharp increase in GA3 content in the indica–japonica tetraploid rice, and upregulated expression of OsAmy3A and OsAmy3D resulted in sharp increase in α-amylase activity, water absorption, and sucrose and fructose contents, which resulted in the seed vigour being greater than that of its parents. The results indicate that additional research on the physiological and molecular features of indica–japonica tetraploid rice seed germination in response to ionizing radiation is needed.

Sequencing of S5 gene in autotetraploid rice japonica and indica to overcome F1 hybrids embryo sac sterility

“…Poor fertility is the main barrier for utilizing heterosis between the two rice (O. sativa L.) subspecies, indica and japonica and the development of autotetraploid hybrids (2n = 4x = 48) has been advised as a new method for increasing heterosis in hybrid rice Ghaleb et al, 2020;Rao et al, 2022). An autotetraploid indica/japonica hybrid combines the advantages of polyploidy and heterosis between indica and japonica (Hu et al, 2010;Yu et al, 2021a;Huang and Huang, 2022;Rao et al, 2022) and realized to have great potential to increase the yield of rice Ghouri et al, 2019;Chen et al, 2021;Ku et al, 2022). Furthermore, autotetraploid indica/japonica hybrids hold more nutrition value than diploid rice (Zhiyong et al, 1987 andChen et al, 2021Ghouri et al, 2023) and therefore said to have stronger potential vigor in rice breeding than diploid rice does (Shahid et al, 2011;Rout et al, 2020;.…”

“…Furthermore, autotetraploid indica/japonica hybrids hold more nutrition value than diploid rice (Zhiyong et al, 1987 andChen et al, 2021Ghouri et al, 2023) and therefore said to have stronger potential vigor in rice breeding than diploid rice does (Shahid et al, 2011;Rout et al, 2020;. Hybrid sterility between two rice subspecies may be overcome by using tetraploid lines followed by intensive selection (Chen et al, 2021;Huang et al, 2022). Also, the gigantic features of the autotetraploid hybrids may establish a plant structure able to support the higher yield (Shen et al, 2022;Zeng et al, 2023).…”

“…According to using polyploidy meiosis stability (PMeS) line as a parent improves embryo development and the seed set rate of a tetraploid rice hybrid. Moreover, polyploidy is widely accepted to play an important role in the evolution and breeding of plant species (Udall and Wendel, 2006;Cheng et al, 2022;Mangena, 2023), but nonetheless, a low seed set rate significantly hindered the development of polyploidy rice breeding Xiong et al, 2019;Zhang et al, 2019, Chen et al, 2021Huang et al, 2022). Consequently, there is an urgent need to overcome sterility of interspecific hybrids of autotetraploid rice in order to utilize its great genetic competence and explore its hybrid vigor.…”