The effect of harpin protein on plant growth parameters, leaf chlorophyll, leaf colour and percentage rotten fruit of pepper plants inoculated with Botrytis cinerea

Scientia Horticulturae (Impact Factor: 1.5). 01/2006; 109(2):107-112. DOI: 10.1016/j.scienta.2006.03.008

ABSTRACT In this study, harpin protein was applied to the peppers (Capsicum annuum L. var. cvs. ‘Demre’, ‘Yalova Charleston’ and ‘Sari Sivri’) grown under natural conditions. These plants were subjected to artificial inoculation with Botrytis cinerea, which causes fruit spoilage in peppers. Changes in vegetative growth, total chlorophyll content in leaves, leaf colour and percentage of rotten fruits were determined after treatments. The number of leaves per plant value was quite low in all cultivars and the plant height value was low only in cv. ‘Sari Sivri’ treated with B. cinerea. Values obtained from vegetative growth parameters in the plants subjected to harpin protein + B. cinerea treatment were only higher than B. cinerea treatment. Leaf chlorophyll values exhibited significant decline in the plants subjected to B. cinerea treatment in all cultivars. However, the chlorophyll content in the plants subjected to harpin protein + B. cinerea treatment was low. The colour values obtained from leaves supported the chlorophyll findings. Fruit spoilage percentages were lower in the fruits picked from the plants of harpin protein + B. cinerea treatment compared with those picked from the plants only subjected to B. cinerea treatment.

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    ABSTRACT: Two field trials were conducted using established apple (Malus cv. Golden Delicious) and pear (Pyrus communis ‘Williams’ Bon Chrétien') to assess the efficacy of three commercially available systemic inducing resistance (SIR) products, Messenger (a.i. Harpin protein), Phoenix (a.i. Potassium phosphite) and Rigel (a.i. Salicylic acid derivative) applied at four different growth stages of tree development (bud break, green cluster, 90% petal fall, early fruitlet) against the foliar pathogens Venturia inaequalis and Venturia pirina which cause apple and pear scab respectively. A conventional synthetic fungicide (penconazole) used within the UK for apple and pear scab control was included for comparison. Little efficacy as scab protectants was demonstrated when each SIR product and penconazole was applied at only two growth stages (bud break, green cluster). However when the above compounds were applied at three or more growth stages efficacy as scab protectants was confirmed. The synthetic fungicide penconazole provided greatest protection against apple and pear scab in both the 2006 and 2007 field trials. There was little difference in the magnitude of scab protection conferred by each SIR agent. Results suggest application of at least three sprays during bud break to early fruitlet formation with an appropriate SIR agent may provide a useful addition to existing methods of apple and pear scab management under field conditions.
    Crop Protection. 01/2009;
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    ABSTRACT: Verticillium wilt, caused by Verticillium dahliae Kleb., is one of the most important diseases of peppers. Harpin is a bio-activator that may be used as an alternative control against insects and fungi. Therefore, the aim of this study was to describe how harpin affected plants that had been inoculated with V. dahliae. Disease severity in harpin+V. dahliae-treated plants was lowered by a rate of 85.5% compared with V. dahliae plants. In the absence of harpin, V. dahliae caused a reduction in the number of leaves per plant and plant height. Values obtained from leaf dry weight and root dry weight parameters in the plants subjected to harpin+V. dahliae were higher than those exposed to just V. dahliae. Leaf chlorophyll values declined significantly in the plants subjected to V. dahliae, and the total chlorophyll results were supported by color values. At the end of the study, spraying pepper plants with harpin during the growth period appeared to be a promising strategy to increase plant resistance and protection against V. dahliae.
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    ABSTRACT: There is a group of compounds containing proteins that activate responses to stress in plants. One of these proteins is harpin, used for an alternative control of insects and fungi, as well as to increase yield and quality for vegetable production. Harpin was applied to foliage to study effects on induced resistance in pepper (Capsicum annuum L.), cvs. Demre and Yalova Charleston, inoculated with Verticillium dahliae Kleb., a pathogen of pepper. Plants grown in a greenhouse were treated with three applications of harpin at 50 g/100 L in water. Changes in stem dry weight, root dry weight, leaf water content and leaves/plant, total chlorophyll content in leaves, leaf color, and leaf defoliation were determined. Reduction in total leaf chlorophyll content was caused by V. dahliae. Values of total leaf chlorophyll content (cv. Demre 13.10 mg/100 L, cv. Yalova Charleston 12.96 mg/100 L) in plants subjected to +harpin +V. dahliae were higher than for those treated with −harpin +V. dahliae (cv. Demre, 6.76 mg/100 L; cv. Yalova Charleston, 7.05 mg/100 L). Leaves/plant and plant height values were lower for V. dahliae inoculated plants. The results indicate that harpin may induce resistance to V. dahliae in peppers.
    International Journal of Vegetable Science 01/2009; 15(3):253-263.