Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China.
Pakistan Forest Institute, Peshawar, Khyber Pakhtun Khawa, KPK, Pakistan.
Cell Mol Biol (Noisy-le-grand). 2024 Sep 8;70(8):182-192. doi: 10.14715/cmb/2024.70.8.26.
Globally, there is a growing concern about tree mortality due to harsh climates and changes in pest and disease patterns. However, experimental studies on the interactions between biotic and abiotic stresses in plants are relatively scarce. In this study, we investigated the interaction between Fusarium solani and water-stressed Dalbergia sissoo saplings. We postulated that under drought conditions, sissoo plants would become more susceptible to dieback infestation. Five fungi, including Fusarium oxysporum, Curvularia lunata, Cladophialophora carrionii, Alternaria alternaria, and Fusarium solani, were isolated from an old shisham tree showing advanced symptoms of dieback infestation. These fungi were identified based on their ITS sequence homology and spore characteristics. Dieback development was more pronounced in plants experiencing water stress, regardless of their predisposition or whether it occurred simultaneously. Lesions were more noticeable and longer in predisposed saplings (3.8cm), followed by simultaneous (2.4cm) and much smaller lesions in seedlings that were inoculated and well-watered (0.24cm). Progressive browning of the upper leaves, which lowers sapling height in predisposed, simultaneous, and well-watered inoculated saplings to 8.09 inches, 5.93 inches, and 17.42 inches, are typical dieback symptoms. Water stress causes the loss of chlorophyll a, b, and carotenoids, which reduces stomatal conductance, transpiration rate, and photosynthetic activity, leading to poor development and mortality. Similarly, predisposed, simultaneous, and well-watered inoculated seedlings expressed increased activity of CAT (22.57, 18.148, and 9.714 U/mg) and POD (3.0, 4.848, 1.246 U/mg), to reduce the damage caused by elevated levels of H2O2 expression. It is concluded that water stress is the main cause of dieback in shisham saplings that subsequently disposed of infected seedlings to secondary agents such as fungi and insects in the advanced stages of the dieback with prolonged drought stress. The lack of dieback in native populations is attributed to the absence of several ecological stresses, including water stress, extended droughts, waterlogging, and salinity. This study emphasizes the need for additional research into the effects of abiotic factors linked with fungal diseases on the long-term production and management of D. sissoo in Pakistan.
全球范围内，由于恶劣的气候和病虫害模式的变化，树木死亡率引起了越来越多的关注。然而，关于植物中生物和非生物胁迫相互作用的实验研究相对较少。在这项研究中，我们调查了尖叶黄檀幼苗与尖孢镰刀菌和水分胁迫之间的相互作用。我们假设在干旱条件下，黄檀幼苗更容易受到枯梢病的侵害。从一棵表现出严重枯梢病症状的老黄檀树上分离出了五种真菌，包括尖孢镰刀菌、旋孢腔菌、卡氏长喙壳菌、链格孢菌和尖孢镰刀菌。这些真菌是根据其 ITS 序列同源性和孢子特征鉴定的。无论是否同时发生，在遭受水分胁迫的植物中，枯梢病的发展更为明显。在易患病的幼苗中，病变更为明显且更长（3.8 厘米），其次是同时发生的（2.4 厘米）和接种并浇水良好的幼苗中的病变更小（0.24 厘米）。受感染的易患病、同时发生和浇水良好的幼苗的上部叶片逐渐变褐，导致幼苗高度降低至 8.09 英寸、5.93 英寸和 17.42 英寸，这是典型的枯梢病症状。水分胁迫导致叶绿素 a、b 和类胡萝卜素的丧失，从而降低气孔导度、蒸腾速率和光合作用，导致生长不良和死亡。同样，易患病、同时发生和浇水良好的接种幼苗的 CAT（22.57、18.148 和 9.714 U/mg）和 POD（3.0、4.848 和 1.246 U/mg）活性增加，以减轻因高水平 H2O2 表达而造成的损害。因此，可以得出结论，水分胁迫是黄檀枯梢病的主要原因，随后在枯梢病的晚期，受感染的幼苗会被二次侵染，如真菌和昆虫等，在干旱胁迫持续时间较长的情况下，枯梢病会进一步发展。在原生种群中没有枯梢病的发生，这归因于缺乏包括水分胁迫、长期干旱、水涝和盐度在内的几种生态胁迫。本研究强调需要进一步研究与真菌病害相关的非生物因素对巴基斯坦黄檀长期生产和管理的影响。
