First evidence of putrescine involvement in mitigating the floral malformation in mangoes: A scanning electron microscope study

Abstract

Floral malformation is the most destructive disease in mangoes. To date, the etiology of this disease has not been resolved. There are indications that stress-stimulated ethylene production might be responsible for the disease. Putrescine mediates various physiological processes for normal functioning and cellular metabolism. Here, the effect of putrescine in concentration ranging from 10(-1) to 10(-3) M was evaluated on disease incidence during mango flowering seasons of 2012 and 2013. In a scanning electron microscopy (SEM) study, putrescine (10(-2) M)-treated malformed floral buds bloomed into opened flowers with separated sepals and/or petals like healthy, whereas the untreated (control) malformed buds remained deformed. Further, malformed flowers recovered upon putrescine treatment, displaying clearly bilobed anthers, enclosing a large number of normal pollen grains and functional ovary with broad stigmatic surface as compared to control. The present findings provide the first report to demonstrate the role of putrescine in reducing various adverse effects of stress ethylene via decelerating the higher pace of its biosynthesis. It stabilizes the normal morphology, development, and functions of malformed reproductive organs to facilitate successful pollination, fertilization, and, thereby, fruit set in mango flowers. However, putrescine-ethylene-mediated cell signaling network, involving various genes to trigger the response, which regulates a wide range of developmental and physiological processes leading to normal cell physiology, needs to be investigated further.

Mango (Mangifera indica L.) malformation: a malady of stress ethylene origin

“…The aborted morphology of each and every reproductive organ in mango inflorescence is due to amplified level of endogenous level of ethylene, which lead to malfunction in fruit development in mango, and also the added load of cyanide, resulted from ethylene biosynthesis, contribute to the progression of necrosis which responsible for dehydration of anther and pistil during oversensitive reaction of plants (Rani et al 2013). Recently, a potential role of ethylene in floral malformation in mango was confirmed via its cross talk with purescine which could result in reduced malformation by mitigating the negative effects of ethylene in malformed mango flower (Singh et al 2014). The ethylene formation can be elicited under various abiotic and biotic stresses.…”

“…Recently, the association of 'F. mangiferae' and 'ethylene' has been suggested (Crespo et al 2014;Singh et al 2014). Here, we discuss the role of ethylene in the development of mango malformation.…”

“…In acute response, 'stress ethylene' exerts adverse effects on the physiology of floral and vegetative tissue leading to loss of function at later stage and thereby mango malformation (Rani et al 2013). Further, ethylene and polyamine cross talk in response to abiotic and biotic stress in cell signaling net work of metabolic processes leading to change in functional morphology in malformed tissues has been established (Singh et al 2014), which fine tune at biochemical and molecular levels might be useful in further research to strengthen the stress physiology in mango malformation (Singh et al 2012;Ansari et al 2013a;Singh et al 2014) (Fig. 3).…”

“…'Ethylene' origin nature of malady Several workers have implicated a role of ethylene in mango malformation (Singh et al 1994;Pant 2000;Bains and Pant 2003;Nailwal et al 2006;Krishnan et al 2009;Rymbai and Rajesh 2011;Ansari et al 2012Ansari et al , 2013aRani et al 2013;Singh et al 2014). Malformin-like substances are in some way concerned to cause malformation by stimulating ethylene production (Singh and Dhillon 1989a).…”

“…Anti-ethylene produces such as aminovinylglycine (AVG) and 1-methylcyclopropene (1-MCP) might be exploited to reduce the adverse effect of ethylene on morphology of mango panicles (Zaharah and Singh 2011;Rani et al 2013). The exogenous application of putrescine caused a channeling of S-adenosyl methionine (SAM) towards polyamine synthesis, which resulted into slowing down the higher pace of ethylene biosynthetic pathway and thereby a drop in ethylene endogenous pool and reduction in panicle malformation (Singh et al 2014). Therefore, further research should be focused in order to nullify the 'stress ethylene' to cope its adverse effects on mango tissues.…”