Morphological and differential gene expression analyses of drought stressed coffee in response to foliar application of abscisio acid (ABA), glulathione (GSH)and salicylic acid (SA)
2017
Heredia, M.C.C. | Ruazol, A. | Ocampo, E.T.M.
Coffea canephora var Robusta is of worldwide importance as a traded commodity. However, attaining high coffee bean yield is hampered by drought. This study analyzed the effects of drought in Robusta coffee genotypes at the morphological and molecular level, as well as the effects of foliar application of abscisic acid (ABA), glutathione (GSH) and salicylic acid (SA) during drought in the most susceptible genotype of the Robusta seedlings. Four genotypes (FRT 11, 7, 23, 65) were subjected to two shade levels (0% and 60% light reduction) and two water supply levels (drought and well-watered) to access genotypic drought response. Significant interactions between the drought, shade and genotype treatments were observed. Among the genotypes, FRT65 performed best while FRT23 exhibited poor tolerance to drought. The identified drought-sensitive FRT23 was then used in another study wherein it is subjected to foliar application of selected compounds. One month recovery followed and the morphological parameters were evaluated. Glutathione (GSH) foliar application resulted in increase in the number of leaves, number of nodes and proliferation of adventitious roots, equaling and even surpassing that of the water treatment. Abscisic acid (ABA) induced growth retardation leaf abscission and senescence. Spraying of salicylic acid (SA) retarted all the vegetative parameters measured. Differential gene expression of four drought related genes in Robusta - CAT, DH3, RBCS, and sHSP affirmed the drought alleviating effects of the foliar spray treatments. The results indicate that GSH was the most efficient in drought alleviation in coffee and that elucidation of GSH on coffee plant metabolism can lead to enhancement of drought tolerance in coffee.
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