Dias Maila P, Bastos Matheus S, Xavier Vanessa B, Cassel Eduardo, Astarita Leandro V, Santarém Eliane R
Laboratório de Biotecnologia Vegetal, Faculdade de Biociências, Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6681, Porto Alegre, RS 90619-900, Brazil.
Laboratório de Operações Unitárias, Faculdade de Engenharia, Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga 6681, Porto Alegre, RS 90619-900, Brazil.
Plant Physiol Biochem. 2017 Sep;118:479-493. doi: 10.1016/j.plaphy.2017.07.017. Epub 2017 Jul 20.
Plant Growth Promoting Rhizobacteria (PGPR) represent an alternative to improve plant growth and yield as well as to act as agents of biocontrol. This study characterized isolates of Streptomyces spp. (Stm) as PGPR, determined the antagonism of these isolates against Pectobacterium carotovorum subsp. brasiliensis (Pcb), evaluated the ability of Stm on promoting growth and modulating the defense-related metabolism of tomato plants, and the potential of Stm isolates on reducing soft rot disease in this species. The VOC profile of Stm was also verified. Promotion of plant growth was assessed indirectly through VOC emission and by direct interaction with Stm isolates in the roots. Evaluation of soft rot disease was performed in vitro on plants treated with Stm and challenged with Pcb. Enzymes related to plant defense were then analyzed in plants treated with three selected isolates of Stm, and PM1 was chosen for further Pcb-challenging experiment. Streptomyces spp. isolates displayed characteristics of PGPR. PM3 was the isolate with efficient antagonism against Pcb by dual-culture. Most of the isolates promoted growth of root and shoot of tomato plants by VOC, and PM5 was the isolate that most promoted growth by direct interaction with Stm. Soft rot disease and mortality of plants were significantly reduced when plants were treated with StmPM1. Modulation of secondary metabolism was observed with Stm treatment, and fast response of polyphenoloxidases was detected in plants pretreated with StmPM1 and challenged with Pcb. Peroxidase was significantly activated three days after infection with Pcb in plants pretreated with StmPM1. Results suggest that Streptomyces sp. PM1 and PM5 have the potential to act as PGPR.
植物促生根际细菌（PGPR）是改善植物生长和产量以及作为生物防治剂的一种替代方法。本研究对链霉菌属（Stm）菌株作为PGPR进行了表征，确定了这些菌株对胡萝卜软腐果胶杆菌巴西亚种（Pcb）的拮抗作用，评估了Stm促进番茄植株生长和调节防御相关代谢的能力，以及Stm菌株在减少该物种软腐病方面的潜力。还验证了Stm的挥发性有机化合物（VOC）谱。通过VOC排放以及与根部的Stm菌株直接相互作用间接评估植物生长促进情况。在经Stm处理并用Pcb挑战的植株上进行体外软腐病评估。然后在经三种选定的Stm菌株处理的植株中分析与植物防御相关的酶，并选择PM1进行进一步的Pcb挑战实验。链霉菌属菌株表现出PGPR的特征。通过双培养，PM3是对Pcb具有有效拮抗作用的菌株。大多数菌株通过VOC促进番茄植株根和茎的生长，而PM5是通过与Stm直接相互作用最能促进生长的菌株。用StmPM1处理植株后，软腐病和植株死亡率显著降低。观察到Stm处理对次生代谢的调节作用，在用StmPM1预处理并用Pcb挑战的植株中检测到多酚氧化酶的快速反应。在用StmPM1预处理的植株中，感染Pcb三天后过氧化物酶被显著激活。结果表明链霉菌属PM1和PM5有潜力作为PGPR发挥作用。
