Scientia Horticulturae 130 (2011) 847–852 Contents lists available at SciVerse ScienceDirect Scientia Horticulturae journa l h o me page: www.elsevier.com/locate/scihorti Pathogenesis-related (PR)-proteins: Chitinase and -1,3-glucanase in defense mechanism against malformation in mango (Mangifera indica L.) Saboki Ebrahim a , K. Usha a,∗ , Bhupinder Singh b a Division of Fruits and Horticultural Technology, Indian Agricultural Research Institute, New Delhi, India b Division of Nuclear Research Laboratory, Indian Agricultural Research Institute, New Delhi, India a r t i c l e i n f o Article history: Received 16 June 2011 Received in revised form 8 September 2011 Accepted 12 September 2011 Keywords: Fusarium mangiferae Floral malformation Mango cultivars Resistance Screening Tolerance a b s t r a c t Mango, the king of fruits in India is cultivated commercially in many tropical and subtropical regions of the world. Undoubtedly, mango malformation is a serious disease affecting mango production in India and many other countries around the world. It is now shown that the malady is inflicted by Fusarium, a fungus, and also that the plants have the capacity to suppress or reduce pathogen attack by inducing the synthesis of antimicrobial metabolites such as chitinase and/or the synthesis of lignin, both of which may enhance plant defense system. The present study was aimed at investigating the variability and relationship between activities of chitinase, -1,3-glucanase and content of lignin in the leaves using 12 mango cultivars with the different degree of resistance to floral malformation. Results revealed that the activity of chitinase and -1,3-glucanase in the leaves were significantly high in mango cultivars resistant to malformation (r = -0.90 and r = -0.91, respectively) during the flowering period, whereas lignin content did not show a significant correlation with malformation. The highest activity of chitinase (1.977–2.011 units) and -1,3-glucanase (80.54–82.06 units) was recorded in resistant mango cultivars Bhadauran and Elaichi. In contrast, these activities were less than 1.010 and 25.21 respectively in highly susceptible mango cultivars such as Amrapali, Eldon and Neelum. Lignin content was highest in resistant cultivar Bhadauran, but it did not show significant relation to the malformation intensity of the cultivars. Thus, leaf chitinase and -1,3-glucanase may be contributing towards resistance to malformation in mango and that the relative activities of these enzymes can be used as a criterion to predict and screen the mango germplasm and cultivars for resistance to floral malformation. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Mango malformation was first reported in 1891 by ‘Marries’ from Darbhanga (Bihar) and since then it has been found widely distributed in the all mango producing regions of India particularly in the northern part (Chib et al., 1984). It has also been reported from most of the mango producing countries around the world such as Egypt, South Africa, Sudan, Senegal, Brazil, Central America, Mexico, USA, Israel, Bangladesh, UAE, Oman, Pakistan and Malaysia (Padron, 1983; Manicom, 1989; Burhan, 1991; Meah and Khan, 1992; Noriega-Cantu et al., 1999; Ploetz et al., 2002; Kvas et al., 2008). Malformed panicles are abnormal, thickened and highly branched, with large number of male flowers (Fig. 1). Floral mal- formation causes serious economic losses in various parts of the world as the affected panicles produce flowers which are sterile or fruits abort immediately after fruit set and as a consequence fruit yields are significantly reduced (Zheng and Ploetz, 2002). As much ∗ Corresponding author. Tel.: +91 9873641003. E-mail address: kalidindi.usha3@gmail.com (K. Usha). as 100% yield loses have been reported in case of highly susceptible mango cultivars. Only few cultivars including Bhadauran (Prasad et al., 1965), Bhadayam Dula, Samar Bahist Rampur and Mian Saheb (Ram Nath and Sachan, 1987), Elaichi (Negi et al., 1996) and Dahiyar (Mishra, 2004) were reported free from this malady in India, while others showed varying percent of malformation incidence ranging from tolerant to highly susceptible especially for most of the commer- cial mango cultivar such as Amrapali, Mallika, Neelum, Chausa, Dashehari, Bombay Green and Langra in Northern part of India. The etiology of malformation has been a contentious issue, and a wide range of biotic and abiotic factors have been reported to cause the disease. Convincing evidence that a fungus causes malformation has been in the literature for decades (Chakrabarti and Ghosal, 1989; Steenkamp et al., 2000; Kumar et al., 2011). The recent discovery that several Fusarium spp. are associated with mango malformation is intriguing. However, only Fusarium mangiferae has been shown to cause mango malformation (Britz et al., 2002; Freeman et al., 2004; Youssef et al., 2006; Marasas et al., 2006; Gamliel-Atinsky et al., 2009; Iqbal et al., 2010; Arif et al., 2011). As malformed shoots have elevated level of fungal infection 0304-4238/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.scienta.2011.09.014