Higher growth induced upon Potato Virus X invasion in Messenger treated tomato p

This investigation aimed to examine the possible role of foliar Messenger (a bio-product based on harpin protein) application in reducing the Potato virus X (PVX) development on tomato plants treated with 3 different doses of Messenger (M1: 0.5g l -1 , M2: 1g l -1 , M3: 0.25g l -1 ). For that reason, seventy-two hours post treatment (hpt) a group of tomato plants was inoculated with PVX. Besides, another group of tomato plants were inoculated 24 hours afterwards to check the effect of plant age on PVX infection. Plants treated with M1 at 72h prior to the PVX inoculation showed the maximum recovery as an increase in chlorophyll content (25.78±0.67), plant height (31±4.58) cm and leaf area (361.07±76.15) cm 2 . However, M1-enhancement in plant height (27±0.4) cm and leaf area (289.83±45.04) cm 2 of the non-inoculated tomato plants was lower than that in the inoculated ones. This indicated that M1 induction was most distinct after viral inoculation with higher growth of tomato plants than before introducing the virus. Furthermore, mature plant resistance against PVX was developed with as short plant age increase as to 24 hours.