In vitro: Response of plant growth regulators and antimalformins on conidia germination of Fusarium mangiferae and incidence of mango malformation

Naphthalene Acetic Acid Potassium Salt (NAA-K+) Affects Conidial Germination, Sporulation, Mycelial Growth, Cell Surface Morphology, and Viability of Fusarium oxysporum f. sp. radici-lycopersici and F. oxysporum f. sp. cubense in Vitro

The response to exogenous addition of naphthalene acetic acid potassium salt (NAA-K⁺) to Fusarium oxysporum f. sp radici-lycopersici ATCC 60095 and F. oxysporum f. sp. cubense isolated from Michoacan Mexico soil is reported. The in vitro study showed that NAA-K⁺ might be effective in the control of Fusarium oxysporum. Exogenous application of NAA-K⁺ affected both spores and mycelium stages of the fungi. Viability testing using acridine orange and propidium iodide showed that NAA-K⁺ possesses fungal killing properties, doing it effectively in the destruction of conidia of this phytopathogenic fungi. Analysis of treated spores by scanning electron microscopy showed changes in the shape factor and fractal dimension. Moreover, NAA-K⁺ repressed the expression of brlA and fluG genes. The results disclosed here give evidence of the use of this synthetic growth factor as a substance of biocontrol that presents advantages, and the methods of application in situ should be explored.

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

Mango malformation is a major constrain in mango production worldwide causing heavy economic losses depending on cultivar type and susceptibility. The malady has variously been ascribed to be acarological, viral, fungal and physiological in nature. Here, we discuss the ethylene origin nature of malady. There are indications that most of the symptoms of mango malformation resemble with those of caused by ethylene effects. Multiple evidence reports of putative causal agents including Fusarium mangiferae to augment the endogenous pool of 'stress ethylene' are well documented. Therefore, over load of 'stress ethylene' impairs morphology malformed tissue and cyanide derived from ethylene biosynthesis causes necrosis and death of malformed cells. This review covers various factors eliciting 'stress ethylene' formation, role of ethylene in development of malady and regulation of ethylene action to reduce malformation in mango.

Role of ethrel in causation of floral malformation in mango cv. Amrapali: a scanning electron microscopy study

Floral malformation is a main constraint to reduce fruit yield in mango plants. Recently, we report on the role of putrescine in normalizing the functional morphology of mango flower by reducing various adverse effects of ethylene. Here, ethrel, an ethylene releasing compound, was exogenously applied to mango plant cv Amrapali to evaluate the response of flower development under high level of ethylene. Scanning electron microscopy (SEM) study showed that ethrel treated flowers were observed to progressively be deformed and remain unbloom. The flower buds were not distinguishable and flower parts such as petals, sepals, anther and stigma were not properly developed. The stamen showed fused anther lobes and carpel depicted curved style with pointed stigma. The findings of present study suggest the involvement of ethylene to abort the functional morphology of flower and thereby development of malformation.