Author(s):

V Rani, G Bains, MW Ansari, AK Tiwary, S Verma, Arun Kumar and SM Prasad

Abstract: Mango holds a significant place in the tropical and subtropical areas of the world. Its fruit are widely appreciated for unique aroma and flavor. But this crop is afflicted by a disorder/disease known as mango malformation. Mango malformation imposes a serious restriction on production of mango in India and other mango cultivating provinces of the world bringing in heavy economic losses. The disease/disorder results in alteration of vegetative and floral tissues of the crop. A broad range of biotic and abiotic factors have been assigned as the etiology of malformation. Several evidences have been put forth to justify the involvement of stress ethylene synthesized in response to low temperature, high relative humidity and a soil borne fungal pathogen during bud inception stage. These stresses induce the accumulation of reactive oxygen species (ROS) in the cells, which can cause severe oxidative damage to the plants, thus inhibiting growth and yield. The equilibrium between the production and scavenging of ROS is commonly known as redox homeostasis. However, when ROS production overwhelms the cellular scavenging capacity, thus unbalancing the cellular redox homeostasis, the result is a rapid and transient excess of ROS, known as oxidative stress. Plants have antioxidant mechanisms for scavenging the excess ROS and prevent damages to cells. It has been shown that ROS have a direct antimicrobial effect on the pathogen also. They are involved in the cross-linking of cell walls around the site of infection and also, activate both local programmed cell death and systemic increase in stress-induced pathogen resistance. The present study compares the expression profile of catalase in normal and afflicted mango leaf tissues. The study revealed the over-expression of catalase in malformed leaves as compared to healthy ones. The results clearly demonstrated that tissues from infected leaves accumulated ROS while their scavenging capacities are decreased or even absent. The suppression of ROS detoxifying mechanisms can be involved in the induction of the disorder.

Pages: 3222-3224  |  1360 Views  293 Downloads

Download (448KB)