State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, PR China.
State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, PR China.
Pestic Biochem Physiol. 2024 Sep;204:106095. doi: 10.1016/j.pestbp.2024.106095. Epub 2024 Aug 20.
Plant growth-promoting rhizobacteria (PGPR) have been reported to suppress various diseases as potential bioagents. It can inhibit disease occurrence through various means such as directly killing pathogens and inducing systemic plant resistance. In this study, a bacterium isolated from soil showed significant inhibition of Valsa mali. Morphological observations and phylogenetic analysis identified the strain as Pseudomonas thivervalensis, named K321. Plate confrontation assays demonstrated that K321 treatment severely damaged V. mali growth, with scanning electron microscopy (SEM) observations showing severe distortion of hyphae due to K321 treatment. In vitro twigs inoculation experiments indicated that K321 had good preventive and therapeutic effects against apple Valsa canker (AVC). Applying K321 on apples significantly enhanced the apple inducing systemic resistance (ISR), including induced expression of apple ISR-related genes and increased ISR-related enzyme activity. Additionally, applying K321 on apples can activate apple MAPK by enhancing the phosphorylation of MPK3 and MPK6. In addition, K321 can promote plant growth by solubilizing phosphate, producing siderophores, and producing 3-indole-acetic acid (IAA). Application of 0.2% K321 increased tomato plant height by 53.71%, while 0.1% K321 increased tomato fresh weight by 59.55%. Transcriptome analysis revealed that K321 can inhibit the growth of V. mali by disrupting the integrity of its cell membrane through inhibiting the metabolism of essential membrane components (fatty acids) and disrupting carbohydrate metabolism. In addition, transcriptome analysis also showed that K321 can enhance plant resistance to AVC by inducing ISR-related hormones and MAPK signaling, and application of K321 significantly induced the transcription of plant growth-related genes. In summary, an excellent biocontrol strain has been discovered that can prevent AVC by inducing apple ISR and directly killing V. mali. This study indicated the great potential of P. thivervalensis K321 for use as a biological agent for the control of AVC.
植物促生根际细菌（PGPR）已被报道可作为潜在的生物制剂抑制多种疾病。它可以通过直接杀死病原体和诱导植物系统抗性等多种方式抑制疾病的发生。在本研究中，从土壤中分离出的一种细菌对苹果腐烂病菌（Valsa mali）表现出显著的抑制作用。形态观察和系统发育分析将该菌株鉴定为假单胞菌属的蒂尔瓦氏菌（Pseudomonas thivervalensis），命名为 K321。平板对峙试验表明，K321 处理严重破坏了 V. mali 的生长，扫描电子显微镜（SEM）观察显示菌丝因 K321 处理而严重变形。在离体接枝试验中，K321 对苹果腐烂病（AVC）具有良好的预防和治疗效果。在苹果上施用 K321 可显著增强苹果诱导系统抗性（ISR），包括诱导苹果 ISR 相关基因的表达和增加 ISR 相关酶的活性。此外，在苹果上施用 K321 可以通过增强 MPK3 和 MPK6 的磷酸化来激活苹果 MAPK。此外，K321 可以通过溶磷、产生铁载体和产生 3-吲哚乙酸（IAA）来促进植物生长。施用 0.2%K321 可使番茄株高增加 53.71%，而施用 0.1%K321 可使番茄鲜重增加 59.55%。转录组分析表明，K321 通过抑制必需膜成分（脂肪酸）的代谢和破坏碳水化合物代谢来破坏细胞膜的完整性，从而抑制 V. mali 的生长。此外，转录组分析还表明，K321 通过诱导 ISR 相关激素和 MAPK 信号通路增强植物对 AVC 的抗性，施用 K321 可显著诱导植物生长相关基因的转录。综上所述，发现了一种优秀的生防菌株，可通过诱导苹果 ISR 和直接杀死 V. mali 来防治 AVC。本研究表明，蒂尔瓦氏菌 K321 具有作为防治 AVC 的生物制剂的巨大潜力。
