State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
Plant Physiol Biochem. 2020 Apr;149:245-255. doi: 10.1016/j.plaphy.2020.02.020. Epub 2020 Feb 15.
Arbuscular mycorrhizal fungi (AMF) can form a symbiotic relationships with most terrestrial plants and play an important role in plant growth and adaptation to various stresses. To study the role of AMF in regulating drought resistance in apple, the effects of drought stress on Malus hupehensis inoculated with AMF were investigated. Inoculation of AMF enhanced apple plants growth. Mycorrhizal plants had higher total chlorophyll concentrations but lower relative electrolyte leakage under drought stress. Mycorrhizal plants increased net photosynthetic rate, stomatal conductance, and transpiration rate under drought stress, however, they showed lower inhibition in the quantum yield of PSII photochemistry. Mycorrhizal plants also had higher superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) enzyme activities under drought conditions. Thus, mycorrhizal plants had lower accumulated MDA, HO, and O than non-mycorrhizal seedlings. Total sugar and proline concentrations also significantly increased, helping maintain the osmotic balance. Furthermore, mitogen-activated protein kinase (MAPK) cascades, which participate in the regulation of responses of plants and microorganisms to biotic and abiotic stress, were up-regulated in apple plants and AMF during drought. We saw that there were at least two motifs that were identical in MAPK proteins and many elements that responded to hormones and stress from these MAPK genes. In summary, our results showed that mycorrhizal colonization enhanced apple drought tolerance by improving gas exchange capacity, increasing chlorophyll fluorescence parameters, creating a greater osmotic adjustment capacity, increasing scavenging of reactive oxygen species (ROS), and using MAPK signals for interactions between AMF and their apple plant hosts.
丛枝菌根真菌（AMF）可以与大多数陆生植物形成共生关系，在植物生长和适应各种胁迫方面发挥着重要作用。为了研究 AMF 在调节苹果抗旱性中的作用，研究了干旱胁迫对接种 AMF 的苹果的影响。AMF 接种增强了苹果植株的生长。在干旱胁迫下，菌根植物的总叶绿素浓度更高，但相对电解质渗漏率更低。在干旱胁迫下，菌根植物增加了净光合速率、气孔导度和蒸腾速率，但 PSII 光化学量子产量的抑制作用较低。在干旱条件下，菌根植物的超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）酶活性也更高。因此，与非菌根幼苗相比，菌根植物的 MDA、HO 和 O 积累量较低。总糖和脯氨酸浓度也显著增加，有助于维持渗透平衡。此外，丝裂原活化蛋白激酶（MAPK）级联反应参与调节植物和微生物对生物和非生物胁迫的反应，在苹果植物和 AMF 中在干旱条件下被上调。我们发现，MAPK 蛋白中至少有两个基序与 MAPK 基因中对激素和胁迫作出反应的许多元件相同。总之，我们的结果表明，菌根定植通过提高气体交换能力、增加叶绿素荧光参数、产生更大的渗透调节能力、增加活性氧（ROS）的清除以及利用 MAPK 信号来增强苹果的抗旱性，从而增强苹果的抗旱性。苹果与 AMF 及其宿主植物之间的相互作用。
