Heat Treatment in Combination with Antagonistic Yeast Reduces Diseases and Elicits the Active Defense Responses in Harvested Cherry Tomato Fruit

Abstract

This study investigated the effects of heat treatment (hot air at 38 degrees C) and antagonistic yeast (Pichia guilliermondii) alone or in combination against postharvest diseases (Botrytis cinerea, Alternaria alternata and Rhizopus nigricans) on cherry tomato fruit, and evaluated the elicitation of active defense responses. Results showed that heat treatment at 38 degrees C for 24 h in combination with P. guilliermondii at 1 x 10(8) CFU mL(-1) was the most effective approach to reduce various infections on cherry tomato fruit's wounds. Moreover, the combined heat and P. guilliermondii treatment stimulated a rapid increase of H(2)O(2) and higher lignin deposition in cherry tomato fruit showing that the oxidative burst and biological synthesis of lignin might play important roles in the fruit's active defense responses. In addition, the reduction of the fruit's susceptibility to pathogens by the combined treatment was positively correlated with higher activities of phenylalanine ammonia-lyase (PAL) and beta-1,3-glucanase in cherry tomato fruits, both of which are associated with plant defense responses.

Effect of calcium chloride in combination with salicylic acid on post-harvest freshness of apples

“…This corresponded with greater accumulations of lignin and phenolic compounds in treatment B apples than in treatment A apples ( Fig. 4C and D), in agreement with previous studies where increased POD and PAL activities were associated with large deposits of lignin (28) and phenolic compounds (3), and improved disease control effects in fruits. The lowest degree of anthracnose rot was identified for combination-treated apples (Fig.…”

“…A classical research of plant pathology suggested that lignin could enhance mechanical resistance to pathogen penetration in fruit wounds (27). Possible mechanisms include supporting and strengthening the cell wall to prevent the cell wall degradation that is triggered by athogenic microorganisms, and facilitation of toxin permeation accompanied by water transport (17,28). Moreover, it has been suggested that increased amounts of phenolic compounds in tissues surrounding fruit wounds can be directly toxic to pathogens, or are synthetic precursors of lignin (3).…”

Use of Nonanal-wax as Postharvest Fungicide of Tomato against <i>Botrytis cinerea</i>

“…POD and PAL are commonly studied in the postharvest biocontrol area and known to be involved in plant disease resistance [52].…”

Combined Effects of Fungicides and Thermotherapy on Post-Harvest Quality of Horticultural Commodities

“…The elicitation of compounds involved in the plant defence as a consequence of hot air treatments at 38 °C during 24-72 hours was further demonstrated on tomato cherry fruit by means of higher lignin deposition, and higher activation of phenylalanine ammonia-lyase and -1,3-glucanase (Zhao et al, 2009;.…”

“…On the other hand, the synergic effect of thermotherapy with the use of antagonist strains of yeasts and sodium bicarbonate was demonstrated against Colletotrichum acutatum and P. expansum in stored apples , as well as of thermotherapy in combination with Cryptococcus laurentii against P. italicum and Rhizopus stolonifer on peach, and with Rhodotorula glutinis against P. italicum on pear storage (Zhang et al, 2007;2008). Prevention of spoilage caused by fungi in cherry tomato was provided by heat treatment at 38 °C (24-72 hours) followed by Pichia guilliermondii application (Zhao et al, 2009;. Other results showed that the combined application of hot air at 38 °C for 36 hours and the same yeast antagonist Pichia guilliermondii was effective in the control of postharvest anthracnose rot of loquat fruit .…”