Slow development allows redundant genes to restore the fertility of rpg1, a TGMS line in Arabidopsis.
Slow development allows redundant genes to restore the fertility of rpg1, a TGMS line in Arabidopsis.
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DOI：
10.1111/tpj.15635
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发表时间：
2021-12
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通讯作者：
Cheng Zhang;Meng-Yi Ren;Wen-Jian Han;Ya-Fei Zhang;Min-Jia Huang;Siyun Wu;Jie Huang;Yun Wang;Zheng Zhang;Zhongnan Yang
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作者：
Cheng Zhang;Meng-Yi Ren;Wen-Jian Han;Ya-Fei Zhang;Min-Jia Huang;Siyun Wu;Jie Huang;Yun Wang;Zheng Zhang;Zhongnan Yang
发育缓慢是拟南芥温敏和光敏核不育系育性恢复的一般机制。rpg 1是一个缺少花粉壁图案形成所必需的原基素的温敏核不育系。在这里，我们发现RPG 1-GFP在小孢子母细胞，小孢子和花粉粒中高度表达，但在补充的转基因系中的绒毡层中不表达，这表明小孢子母细胞是primexine形成的主要孢子体细胞。进一步的细胞学观察表明，在缓慢生长条件下，rpg 1的primexine形成部分恢复，导致其育性恢复。RPG 2是拟南芥中RPG 1的同源物。结果表明，在低温条件下，rpg 1和rpg 2的育性恢复率显著低于rpg 1。RPG 2-GFP（WT）转基因株系的小孢子母细胞中也表达RPG 2-GFP蛋白。这些结果表明，RPG 2在rpg 1育性恢复中起着多余的作用。rpg 1植株在生长早期为雄性不育，而在发育后期其育性得到部分恢复。rpg 1侧枝的生育力也部分恢复。进一步的生长分析表明，生殖后期或侧枝生长缓慢导致育性恢复。这项工作揭示了基因冗余在温敏核不育系育性恢复中的重要性，并为花粉壁图案的形成提供了进一步的见解。
Slow development has been shown to be a general mechanism to restore the fertility of thermosensitive and photoperiod-sensitive genic male sterile (TGMS and PGMS) lines in Arabidopsis. rpg1 is a TGMS line defective in primexine, which is essential for pollen wall pattern formation. Here, we showed that RPG1-GFP was highly expressed in microsporocytes, microspores and pollen grains but not in the tapetum in the complemented transgenic line, suggesting that microsporocytes are the main sporophytic cells for primexine formation. Further cytological observations showed that primexine formation in rpg1 was partially restored under slow growth conditions, leading to its fertility restoration. RPG2 is the homolog of RPG1 in Arabidopsis. We revealed that the fertility recovery of rpg1 rpg2 was significantly reduced compared with that of rpg1 under low temperature. The RPG2-GFP protein was also expressed in microsporocytes in the RPG2-GFP (WT) transgenic line. These results suggest that RPG2 plays a redundant role in rpg1 fertility restoration. rpg1 plants were male sterile at the early growth stage, while their fertility was partially restored at the late developmental stage. The fertility of the rpg1 lateral branches was also partially restored. Further growth analysis showed that slow growth at the late reproductive stage or on the lateral branches led to fertility restoration. This work reveals the importance of gene redundancy in fertility restoration for TGMS lines and provides further insight into pollen wall pattern formation.