Transcription elongation factors OsSPT4 and OsSPT5 are essential for rice growth and development and act with APO2.

Jiajun Liu, Wanrong Jie, Xi'an Shi, Yanfeng Ding, Chengqiang Ding

Plant cell reports 2023 Jul

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The transcription elongation factor SPT4/SPT5 complex is essential for rice vegetative and reproductive growth and that OsSPT5-1, with its interactor APO2, is involved in multiple phytohormone pathways. The SPT4/SPT5 complex is a transcription elongation factor that regulates the processivity of transcription elongation. However, our understanding of the role of SPT4/SPT5 complex in developmental regulation remains limited. Here, we identified three SPT4/SPT5 genes (OsSPT4, OsSPT5-1, and OsSPT5-2) in rice, and investigated their roles in vegetative and reproductive growth. These genes are highly conserved with their orthologs in other species. OsSPT4 and OsSPT5-1 are widely expressed in various tissues. By contrast, OsSPT5-2 is expressed at a relatively low level, which could cause osspt5-2 null mutants have no phenotypes. Loss-of-function mutants of OsSPT4 and OsSPT5-1 could not be obtained; their heterozygotes showed severe reproductive growth defects. An incomplete mutant line (osspt5-1#12) displayed gibberellin-related dwarfed defects and a weak root system at an early vegetative phase, and a short life cycle in different planting environments. Furthermore, OsSPT5-1 interacts with the transcription factor ABERRANT PANICLE ORGANIZATION 2 (APO2) and plays a similar role in regulating the growth of rice shoots. RNA sequencing analysis verified that OsSPT5-1 is involved in multiple phytohormone pathways, including gibberellin, auxin, and cytokinin. Therefore, the SPT4/SPT5 complex is essential for both vegetative and reproductive growth in rice. © 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Citation

Jiajun Liu, Wanrong Jie, Xi'an Shi, Yanfeng Ding, Chengqiang Ding. Transcription elongation factors OsSPT4 and OsSPT5 are essential for rice growth and development and act with APO2. Plant cell reports. 2023 Jul;42(7):1217-1231