Comparative cytological and transcriptome analyses of ny2 mutant delayed degeneration of tapetal cells and promotes abnormal microspore development in neo-tetraploid rice
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
Frontiers
Abstract
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.
Description
This study provided a new understanding of the genetic basis for pollen fertility and development in neo-tetraploid rice.
Keywords
Rice, RNA-Seq, Pollen sterility, Carbohydrate metabolism, Tapetum