Vigani Gianpiero, Rolli Eleonora, Marasco Ramona, Dell'Orto Marta, Michoud Grégoire, Soussi Asma, Raddadi Noura, Borin Sara, Sorlini Claudia, Zocchi Graziano, Daffonchio Daniele
Department of Life Sciences and Systems Biology, University of Turin, Plant Physiology Unit, 10135, Turin, Italy.
Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, 20133, Milan, Italy.
Environ Microbiol. 2018 May 22. doi: 10.1111/1462-2920.14272.
It has been previously shown that the transgenic overexpression of the plant root vacuolar proton pumps H -ATPase (V-ATPase) and H -PPase (V-PPase) confer tolerance to drought. Since plant-root endophytic bacteria can also promote drought tolerance, we hypothesize that such promotion can be associated to the enhancement of the host vacuolar proton pumps expression and activity. To test this hypothesis, we selected two endophytic bacteria endowed with an array of in vitro plant growth promoting traits. Their genome sequences confirmed the presence of traits previously shown to confer drought resistance to plants, such as the synthesis of nitric oxide and of organic volatile organic compounds. We used the two strains on pepper (Capsicuum annuum L.) because of its high sensitivity to drought. Under drought conditions, both strains stimulated a larger root system and enhanced the leaves' photosynthetic activity. By testing the expression and activity of the vacuolar proton pumps, H -ATPase (V-ATPase) and H -PPase (V-PPase), we found that bacterial colonization enhanced V-PPase only. We conclude that the enhanced expression and activity of V-PPase can be favoured by the colonization of drought-tolerance-inducing bacterial endophytes.
先前的研究表明，植物根部液泡质子泵H -ATPase（V-ATPase）和H -PPase（V-PPase）的转基因过表达赋予植物耐旱性。由于植物根部内生细菌也能促进植物的耐旱性，我们推测这种促进作用可能与宿主液泡质子泵表达和活性的增强有关。为了验证这一假设，我们选择了两种具有一系列体外促进植物生长特性的内生细菌。它们的基因组序列证实了先前已证明能赋予植物抗旱性的特性的存在，如一氧化氮和有机挥发性有机化合物的合成。由于辣椒（Capsicuum annuum L.）对干旱高度敏感，我们用这两种菌株处理辣椒。在干旱条件下，两种菌株都促进了更大根系的形成，并增强了叶片的光合活性。通过检测液泡质子泵H -ATPase（V-ATPase）和H -PPase（V-PPase）的表达和活性，我们发现细菌定殖仅增强了V-PPase。我们得出结论，诱导耐旱的细菌内生菌的定殖可以促进V-PPase表达和活性的增强。
