Damankeshan Bahareh, Shamshiri Mohammad Hosein, Alaei Hosein
Department of Horticultural Science, College of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
Department of Plant Pathology, College of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
Braz J Microbiol. 2024 Mar;55(1):759-775. doi: 10.1007/s42770-023-01216-7. Epub 2023 Dec 29.
Date palm, typically considered a salinity-resistant plant, grows in arid and semi-arid regions worldwide, and experiences decreased growth and yields under salt stress. This study investigates the efficacy of endophytic fungi (EF) in enhancing the salinity tolerance of date palm seedlings. In this experiment, EF were isolated from date tree roots and identified morphologically. Following molecular identification, superior strains were selected to inoculate date palm seedlings (Phoenix dactylifera L., cv. Mazafati). The seedlings were subjected to varying levels of salinity stress for 4 months, utilizing a completely randomized factorial design with two factors: fungal strain type (six levels) and salinity stress (0, 100, 200, and 300 mM sodium chloride). The diversity analysis of endophytic fungi in date palm trees revealed that the majority of isolates belonged to the Ascomycota family, with Fusarium and Alternaria being the most frequently isolated genera. In this research, the application of fungal endophytes resulted in increased dry weight of roots, shoots, root length, plant height, and leaf number. Additionally, EF symbiosis with date palm seedling roots led to a reduction in sodium concentration and an increase in potassium and phosphorus concentrations in aerial parts under salt-stress conditions. While salinity elevated lipid peroxidation, consequently increasing malondialdehyde (MDA) levels, EF mitigated damage from reactive oxygen species (ROS) by enhancing antioxidant enzyme activity, including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), while promoting proline and total soluble sugar (TSS) accumulation. The colonization percentage generally increased with salinity stress intensity in most strains. According to the results, the application of EF can alleviate the adverse effects of salinity stress and enhance the growth of date palm seedlings under saline conditions.
海枣通常被认为是一种耐盐植物，生长在世界各地的干旱和半干旱地区，在盐胁迫下生长和产量会下降。本研究调查了内生真菌（EF）提高海枣幼苗耐盐性的效果。在本实验中，从海枣树根部分离出内生真菌并进行形态学鉴定。经过分子鉴定后，选择优良菌株接种海枣幼苗（Phoenix dactylifera L.，品种Mazafati）。利用完全随机析因设计，将幼苗置于不同水平的盐胁迫下4个月，该设计有两个因素：真菌菌株类型（六个水平）和盐胁迫（0、100、200和300 mM氯化钠）。海枣内生真菌的多样性分析表明，大多数分离株属于子囊菌门，镰刀菌属和链格孢属是最常分离到的属。在本研究中，内生真菌的应用导致根、茎干重增加，根长、株高和叶片数量增加。此外，在盐胁迫条件下，内生真菌与海枣幼苗根系共生导致地上部分钠浓度降低，钾和磷浓度增加。虽然盐胁迫提高了脂质过氧化作用，从而增加了丙二醛（MDA）水平，但内生真菌通过增强抗氧化酶活性（包括超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX））减轻了活性氧（ROS）的损伤，同时促进了脯氨酸和总可溶性糖（TSS）的积累。在大多数菌株中，定殖率通常随着盐胁迫强度的增加而增加。根据结果，内生真菌的应用可以缓解盐胁迫的不利影响，并促进海枣幼苗在盐渍条件下的生长。
