Heat shock-induced resistance in tomato: molecular mechanism and the utilization in practical field
Heat shock-induced plant resistance

The acquisition of higher levels of stress tolerance is of utmost importance to plants for survival. Plants adapt to heat stress through the long-term evolutionary manifestation of developmental and morphological changes and short-term acclimation mechanisms, such as leaf orientation and transpirational cooling. Similar mechanisms may be used to overcome other stresses, overlapping the response ranges and placing emphasis on cellular and physiological strategies that have a broad and overreaching adaptation mechanism. Plant HSR leads to the acquisition of tolerance against many other stress conditions. Cross-protection has been reported between heat stress, dehydration/drought, cold/chilling/freezing, salt stress, and disease. The enhanced disease resistance in plants following the heat stress condition has been known as heat shock-induced resistance (HSIR). HS treatment is reported to accumulate salicylic acid (SA), an important signal molecule in systemic acquired resistance (SAR), as well as to induce resistance against crown rot fungus Colletotrichum gleosporioides in strawberries, Botrytis cinerea in melons and cucumbers, and Pseudomonas syringae in tomato.
Practical application of heat shock treatment
High-temperature treatments have been shown as prospective methods to protect plants against diseases as an alternative to chemicals or fungicides. Effective control of the disease has generally been achieved by hot water treatment, which consists of the exposure of plant material to water at a predetermined temperature for a predetermined time. Furthermore hot water spraying (HWS) has been suggested as a practical means of activating HSIR and directly inhibiting pathogen growth. The prototype of a hot water sprayer device has been developed in a previous study, and it was proven to effectively protect cucumbers against gray mold, as well as induce the accumulation of SA and the expression of the peroxidase gene in leaves. However, the implementation of a sprayer prototype under field conditions was laborious because the sprayer had to be manually operated and was not designed to spray multiple seedlings simultaneously. Here, an improved design of hot water sprayer device was evaluated.

Publication:
- Arofatullah NA, Hasegawa M, Tanabata S, Ogiwara I, Sato T. Heat Shock-Induced Resistance against Pseudomonas syringae pv. tomato (Okabe) Young et al. via Heat Shock Transcription Factors in Tomato. Agronomy. 2019; 9(1):2. https://www.mdpi.com/2073-4395/9/1/2
- Arofatullah NA, Widiastuti A, Chinta YD, Kobayashi T. Prevention of Powdery Mildew Disease in Tomato Nursery by Improved Hot Water Spraying Device. Japanese Journal of Farm Work Research. 2019;15–24.