Transcriptome Analysis Reveals Photoperiod-Associated Genes Expressed in Rice Anthers.

Shiyu Sun,Wanqi Liang,Duoxiang Wang,Wenguo Cai,Yaqi Lei,Xiangxiang Zhao,Jingbin Li,Dabing Zhang,Gang Li

doi:10.3389/fpls.2021.621561

Abstract

Environmental conditions, such as photoperiod and temperature, can affect male fertility in plants. While this feature is heavily exploited in rice to generate male-sterile lines for hybrid breeding, the underlying molecular mechanisms remain largely unknown. In this study, we use a transcriptomics approach to identify key genes and regulatory networks affecting pollen maturation in rice anthers in response to different day lengths. A total of 11,726 differentially expressed genes (DEGs) were revealed, of which 177 were differentially expressed at six time points over a 24-h period. GO enrichment analysis revealed that genes at all time points were enriched in transport, carbohydrate, and lipid metabolic processes, and signaling pathways, particularly phytohormone signaling. In addition, co-expression network analysis revealed four modules strongly correlated with photoperiod. Within these four modules, 496 hub genes were identified with a high degree of connectivity to other photoperiod-sensitive DEGs, including two previously reported photoperiod- and temperature-sensitive genes affecting male fertility, Carbon Starved Anther and UDP-glucose pyrophosphorylase, respectively. This work provides a new understanding on photoperiod-sensitive pollen development in rice, and our gene expression data will provide a new, comprehensive resource to identify new environmentally sensitive genes regulating male fertility for use in crop improvement.

Highlights

Hybrid breeding has made a great contribution to the yield increase of rice (Oryza sativa) relative to inbred varieties, with improvements of up to 20% (Khush, 2001; Michel et al, 2001; Yuan, 2004; Cheng et al, 2007)
Anther differentially expressed genes (DEGs) at All Time Points A total of 177 genes were differentially expressed at all time points in SD and LD anthers (Figure 1C)
We have conducted the first genome-wide transcriptomic and gene network analysis of anthers grown under short and long day lengths and revealed functional and regulatory genes that respond to photoperiod

Summary

INTRODUCTION

Hybrid breeding has made a great contribution to the yield increase of rice (Oryza sativa) relative to inbred varieties, with improvements of up to 20% (Khush, 2001; Michel et al, 2001; Yuan, 2004; Cheng et al, 2007). Since photoperiod is more stable and predictable than temperature, breeders have focused on PGMS lines Several genes, such as photoperiod-sensitive male sterility-1 (pms1) (Zhou et al, 2011; Fan et al, 2016), pms (Zhang et al, 1994), pms (Ding et al, 2012a,b; Zhou et al, 2012), Programmed Cell Death 5 (OsPDCD5) (Wang Y. et al, 2010), and Carbon Starved Anther (CSA) (Zhang et al, 2013), have been reported to control PGMS. A TGMS line currently used for hybrid seed production, thermosensitive genic male sterile 5 (tms5), has been shown to contain a mutation in a conserved ribonuclease, RNase Z (Zhou et al, 2014) These findings reveal the complexity of the interaction between genetic components and environmental signals in determining male fertility in plants (Kim and Zhang, 2018). This work provides insights into the molecular mechanisms of photoperiod-dependent male fertility, which can lead to identification of new PGMS genes for hybrid breeding

MATERIALS AND METHODS

DISCUSSION

DATA AVAILABILITY STATEMENT