Screening of plant immune elicitors and their control effects on tomato yellow leaf curl virus disease

Tomato yellow leaf curl virus disease (TYLCV) is a devastating disease in tomato industry development. Due to the lack of efficient chemical control agents, the prevention and control of this disease has become a major challenge in the industry. This study used the self-bred tomato variety "Nongbo Fen 18109" as experimental material. Through determination of endogenous hormone contents, defense enzyme activities, and viral load in tomato leaves as core indicators, screening experiments of plant immune elicitors were conducted, and further evaluation of the selected elicitors' field control effects on TYLCV was performed. The results showed that 5% amino-oligosaccharin aqueous solution and 6% oligosaccharin-chain protein wettable powder could significantly regulate the balance of tomato endogenous hormones, increase indole-3-acetic acid (IAA), salicylic acid (SA) contents and peroxidase (POD) activity, reduce jasmonic acid (JA) and abscisic acid (ABA) levels, and effectively enhance plant resistance to TYLCV. When used in combination, these two elicitors achieved the best control effect, with only 6 diseased plants during the experimental period and an average CT value of 14.34 in virus detection, significantly superior to single elicitor treatments and the chemical agent moroxydine hydrochloride-copper treatment. This study identified an efficient TYLCV immune elicitor combination and its application effects, providing theoretical basis and practical technical support for constructing a green prevention and control system for tomato yellow leaf curl virus disease.