Yan Yan, Wang Meng-Lu, Zhang Zhen, Liu Guoyu, Wei Wen-Xin, Shi Xin-Tian, Lan Chen, Zhang Xuebin, Xu Shengchun, Shehzad Baloch Faheem, Rasheed Awais, Ni Zhongfu, Sun Qixin, Gou Jin-Ying
Frontiers Science Center for Molecular Design Breeding (MOE), China Agricultural University, Beijing 100193, China; Xianghu Laboratory, Hangzhou 311231, China; School of Life Sciences, Fudan University, Shanghai 200438, China.
Frontiers Science Center for Molecular Design Breeding (MOE), China Agricultural University, Beijing 100193, China.
J Adv Res. 2025 Aug;74:137-151. doi: 10.1016/j.jare.2025.04.048. Epub 2025 Apr 30.
Stripe rust caused by Puccinia striiformis Westend. f. sp. tritici (Pst) is a highly destructive wheat disease that threatens global food security. Pst extracts energy from wheat by interfering with photosynthesis, leading to significant yield losses. Redirecting metabolite flux to counteract pathogens remains a major challenge in enhancing crop resilience.
The primary objective of this study is to clarify the regulations of sucrose synthesis in wheat during its interaction with Pst, especially in relation to susceptibility and resistance response, and to supply genetic resources for breeding programs dedicated to ensuring food security.
Utilizing bulked segregant RNA sequencing (BSR-Seq), we identified and cloned a novel susceptibility (S) gene, sucrose 6 - phosphate synthase 1 (SPS1). We investigated the transcriptional and post-translational regulations of SPS1 by Pst, the wheat APETALA2 transcription factor (wAP2), and Wheat Kinase START 1 (WKS1, Yr36) in transgenic plants using molecular and biochemical approaches. Sugar content variations were analyzed using gas chromatography-mass spectrometry (GC/MS) and colorimetric assays, while Pst infection dynamics were examined by staining or quantifying biomass and uredinial pustule densities.
Targeted mutagenesis of the Pst-inducible SPS1-B gene significantly reduced sucrose content accumulation and restricted Pst growth without compromising yield. In contrast, over-expressing SPS1-B enhanced Pst growth, confirming its role as a susceptibility (S) gene to Pst. Pst upregulated SPS1-B under optimal conditions, enhancing its own pathogenic success. Conversely, wAP2 suppressed SPS1-B transcription, reduced SPS1 protein level, and inhibited Pst infection intensity in transgenic wheat lines. Moreover, WKS1, a high-temperature adult-plant resistance protein, bound, phosphorylated, and suppressed SPS1-B at the post-translational level.
This study identifies SPS1-B as a pivotal molecular switch in sucrose metabolism hijacked by Pst to support its infection. The characterization of SPS1-B and its upstream regulators provides multiple genetic targets for enhancing wheat resistance against stripe rust.
由条形柄锈菌小麦专化型（Puccinia striiformis Westend. f. sp. tritici，Pst）引起的条锈病是一种极具破坏性的小麦病害，威胁着全球粮食安全。Pst通过干扰光合作用从小麦中获取能量，导致显著的产量损失。在增强作物抗逆性方面，重新引导代谢物通量以对抗病原体仍然是一项重大挑战。
本研究的主要目的是阐明小麦与Pst相互作用期间蔗糖合成的调控机制，特别是与感病和抗病反应相关的机制，并为致力于确保粮食安全的育种计划提供遗传资源。
利用混合分离群体RNA测序（BSR-Seq），我们鉴定并克隆了一个新的感病（S）基因，蔗糖6-磷酸合酶1（SPS1）。我们使用分子和生化方法研究了Pst、小麦APETALA2转录因子（wAP2）和小麦激酶START 1（WKS1，Yr36）对转基因植物中SPS1的转录和翻译后调控。使用气相色谱-质谱联用仪（GC/MS）和比色法分析糖含量变化，同时通过染色或量化生物量和夏孢子堆密度来检测Pst感染动态。
对Pst诱导的SPS1-B基因进行靶向诱变显著降低了蔗糖含量积累，并限制了Pst生长，同时不影响产量。相反，过表达SPS1-B增强了Pst生长，证实其作为Pst感病（S）基因的作用。在最佳条件下，Pst上调SPS1-B，增强其自身的致病成功率。相反，wAP2抑制SPS1-B转录，降低SPS1蛋白水平，并抑制转基因小麦品系中的Pst感染强度。此外，高温成株抗性蛋白WKS1在翻译后水平结合、磷酸化并抑制SPS1-B。
本研究确定SPS1-B是Pst劫持的蔗糖代谢中的关键分子开关，以支持其感染。SPS1-B及其上游调节因子的表征为增强小麦对条锈病抗性提供了多个遗传靶点。
