Pan Yufang, Li Qiaofeng, Wang Zhizheng, Wang Yang, Ma Rui, Zhu Lili, He Guangcun, Chen Rongzhi
State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430070, China.
BMC Genomics. 2014 Dec 16;15(1):1114. doi: 10.1186/1471-2164-15-1114.
Thermosensitive genic male sterile (TGMS) lines and photoperiod-sensitive genic male sterile (PGMS) lines have been successfully used in hybridization to improve rice yields. However, the molecular mechanisms underlying male sterility transitions in most PGMS/TGMS rice lines are unclear. In the recently developed TGMS-Co27 line, the male sterility is based on co-suppression of a UDP-glucose pyrophosphorylase gene (Ugp1), but further study is needed to fully elucidate the molecular mechanisms involved.
Microarray-based transcriptome profiling of TGMS-Co27 and wild-type Hejiang 19 (H1493) plants grown at high and low temperatures revealed that 15462 probe sets representing 8303 genes were differentially expressed in the two lines, under the two conditions, or both. Environmental factors strongly affected global gene expression. Some genes important for pollen development were strongly repressed in TGMS-Co27 at high temperature. More significantly, series-cluster analysis of differentially expressed genes (DEGs) between TGMS-Co27 plants grown under the two conditions showed that low temperature induced the expression of a gene cluster. This cluster was found to be essential for sterility transition. It includes many meiosis stage-related genes that are probably important for thermosensitive male sterility in TGMS-Co27, inter alia: Arg/Ser-rich domain (RS)-containing zinc finger proteins, polypyrimidine tract-binding proteins (PTBs), DEAD/DEAH box RNA helicases, ZOS (C2H2 zinc finger proteins of Oryza sativa), at least one polyadenylate-binding protein and some other RNA recognition motif (RRM) domain-containing proteins involved in post-transcriptional processes, eukaryotic initiation factor 5B (eIF5B), ribosomal proteins (L37, L1p/L10e, L27 and L24), aminoacyl-tRNA synthetases (ARSs), eukaryotic elongation factor Tu (eEF-Tu) and a peptide chain release factor protein involved in translation. The differential expression of 12 DEGs that are important for pollen development, low temperature responses or TGMS was validated by quantitative RT-PCR (qRT-PCR).
Temperature strongly affects global gene expression and may be the common regulator of fertility in PGMS/TGMS rice lines. The identified expression changes reflect perturbations in the transcriptomic regulation of pollen development networks in TGMS-Co27. Findings from this and previous studies indicate that sets of genes involved in post-transcriptional and translation processes are involved in thermosensitive male sterility transitions in TGMS-Co27.
温敏核雄性不育（TGMS）系和光周期敏感核雄性不育（PGMS）系已成功用于杂交育种以提高水稻产量。然而，大多数PGMS/TGMS水稻系雄性不育转换的分子机制尚不清楚。在最近培育的TGMS-Co27系中，雄性不育是基于对一个UDP-葡萄糖焦磷酸化酶基因（Ugp1）的共抑制，但需要进一步研究以充分阐明其中涉及的分子机制。
对在高温和低温条件下生长的TGMS-Co27和野生型合江19（H1493）植株进行基于微阵列的转录组分析，结果显示在两种品系、两种条件或两者兼有的情况下，代表8303个基因的15462个探针集存在差异表达。环境因素强烈影响整体基因表达。一些对花粉发育重要的基因在高温下的TGMS-Co27中受到强烈抑制。更显著的是，对在两种条件下生长的TGMS-Co27植株之间的差异表达基因（DEG）进行系列聚类分析表明，低温诱导了一个基因簇的表达。发现该基因簇对育性转换至关重要。它包括许多与减数分裂阶段相关的基因，这些基因可能对TGMS-Co27中的温敏雄性不育很重要，尤其是：富含精氨酸/丝氨酸结构域（RS）的锌指蛋白、多嘧啶序列结合蛋白（PTB）、DEAD/DEAH盒RNA解旋酶、ZOS（水稻C2H2锌指蛋白）、至少一种聚腺苷酸结合蛋白以及其他一些参与转录后过程的含RNA识别基序（RRM）结构域的蛋白、真核起始因子5B（eIF5B）、核糖体蛋白（L37、L1p/L10e、L27和L24）、氨酰-tRNA合成酶（ARS）、真核延伸因子Tu（eEF-Tu）以及一种参与翻译的肽链释放因子蛋白。通过定量RT-PCR（qRT-PCR）验证了12个对花粉发育、低温响应或TGMS重要的DEG的差异表达。
温度强烈影响整体基因表达，可能是PGMS/TGMS水稻系育性的共同调节因子。所确定的表达变化反映了TGMS-Co27中花粉发育网络转录组调控的扰动。本研究及先前研究的结果表明，参与转录后和翻译过程的基因集参与了TGMS-Co27中的温敏雄性不育转换。
