Research Articles (ZERI)

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Browsing Research Articles (ZERI) by Author "Liu, Xiangdong"

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    Comparative cytological and transcriptome analyses of ny2 mutant delayed degeneration of tapetal cells and promotes abnormal microspore development in neo-tetraploid rice
    (Frontiers, 2023) Kamara, Nabieu; Jiao, Yamin; Huang, Weicong; Cao, Lichong; Zhu, Lianjun; Zhao, Chongchong; Huang, Xu; Shivute, Fimanekeni N.; Liu, Xiangdong; Wu, Jinwen; Shahid, Muhammad Qasim
    We aimed to investigate the genetic defects related to pollen development and infertility in NY2, a novel tetraploid rice germplasm known as Neo-tetraploid rice. This rice variety was created through the crossbreeding and selective breeding of various autotetraploid rice lines and has previously shown high fertility. Our previous research has revealed that the NY2 gene, encoding a eukaryotic translation initiation factor 3 subunit E, regulates pollen fertility. However, the underlying mechanism behind this fertility is yet to be understood. To shed light on this matter, we performed a combined cytological and transcriptome analysis of the NY2 gene. Cytological analysis indicated that ny2 underwent abnormal tapetal cells, microspore, and middle layer development, which led to pollen abortion and ultimately to male sterility. Genetic analysis revealed that the F1 plants showed normal fertility and an obvious advantage for seed setting compared to ny2. Global gene expression analysis in ny2 revealed a total of 7545 genes were detected at the meiosis stage, and 3925 and 3620 displayed upregulation and downregulation, respectively. The genes were significantly enriched for the gene ontology (GO) term “carbohydrate metabolic process. Moreover, 9 genes related to tapetum or pollen fertility showed downregulation, such as OsABCG26 (ATP Binding Cassette G26), TMS9-1 (Thermosensitive Male Sterility), EAT1 (Programmed cell death regulatory), KIN14M (Kinesin Motor), OsMT1a (Metallothionein), and OsSTRL2 (Atypical strictosidine synthase), which were validated by qRT-PCR. Further analyses ofDEGs identified nine down-regulated transcription factor genes related to pollen development. NY2 is an important regulator of the development of tapetum and microspore. The regulatory gene network described in this study may offer important understandings into the molecular processes that underlie fertility control in tetraploid rice.
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    In vitro induction of auto‑allotetraploid in a newly developed wild rice line from Oryza alta Swallen
    (2019) Zhang, Liusheng; Shivute, Fimanekeni Ndaitavela; Shahid, Muhammad Qasim; Kamara, Nabieu; Wu, Jinwen; Liu, Xiangdong
    Oryza alta Swallen is an important germplasm for rice resistance breeding; however, its CCDD genome (2n = 48) resulted in low crossability when the wild rice was crossed with O. sativa and restricted the success of transferring the desirable traits into cultivated rice. Induction of polyploidy is an efficient way for overcoming the low crossability among different species. A new O. alta line, Huaye 5, was developed by our group in 2016, which had high fertility (64.93%) and photoperiod-insensitive. Huaye 5 was used to induce auto-allotetraploidy using tissue culture in the present study. The tissue culture system was established by comparing five basic media (N6, B5, MS, NB and MB), two hormones (2,4-D and 6-BA) for induction and two differentiation media (MS and NB), and then induced auto-allotetraploid in the wild rice line by colchicine. The medium and hormone combinations of NB + 2,4-D (2.5 mg/L) + 6-BA (1.0 mg/L) produced the induction rate of 20%, and MS medium was found to be a suitable medium for callus induction with a differentiation rate of 10.15%, and the treatment of 600 mg/L colchicine for 24 h was the best protocol for inducing auto-allotetraploid. Subsequently, auto-allotetraploid plants (2n = 96) were obtained in the present study and their ploidy levels were detected by using flow cytometry, stomata size and chromosomes count methods. Many inclusions in the parenchyma cells surrounding vascular bundle were observed in auto-allotetraploid rice compared to the parent. We developed a new germplasm from O. alta, and established a protocol of in vitro induction of auto-allotetraploid, which can be used for crossing with autotetraploid rice.