EFFECTS OF DROUGHT AND SALINITY TO THE GROWTH, CHLOROPHYLL CONTENT AND EXPRESSION PROFILES OF GENES MAPSAL, MAPYROXYD1, MALHCA1, AND MAFBA6 IN BANANA PLANTLETS (MUSA ACUMINATA, COLLA)

• Main Author: Hidayanti, Nurina
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/76590
• Institution: Institut Teknologi Bandung

Banana (Musa spp.) is a plant that susceptible to water stress. Water deficiency is caused by drought and salinity. Both of these stresses cause osmotic stress which inhibits the growth, development and yield of banana plants. Osmotic stress induces reactive oxygen species (ROS) which results in oxidative stress in banana plants. Oxidative stress disrupts many important bioprocesses in banana plants, including photosynthesis. Photosynthesis-related genes affected by drought and salinity stress include the photosystem I sub unit I gene (MaPSAL) which plays a role in the photosystem-electron transfer chain, the pyridine nucleotide disulfide oxidoreductase gene (MaPYROXYD1) which plays a role in chlorophyll biosynthesis, the chlorophyll a-b binding protein 6 gene (MaLHCA1) which plays a role in the light harvesting complex, and the Aldolase superfamily protein gene (MaFBA6) which plays a role in the calvin cycle. This study aims to analyze the effect of drought stress and salinity stress on growth, chlorophyll content, and photosynthesis-related gene expression in banana plantlets. Banana plantlets were cultured in vitro on Murhasige and Skoog medium with 10% PEG6000 and 100 mM NaCl to mimic drought and salinity stress condition. This study measured the growth of banana plantlets consisting of banana plantlet height, number of leaves and fresh weight of banana plantlets. Chlorophyll content was measured using the spectrophotometric method. Gene expression was analyzed by qPCR. The results of observations on the growth of banana plantlets under drought and salinity stress showed differences in the height and weight of banana plantlets. Banana plantlets under salinity stress had the lowest height when compared to plantlets under drought stress and without stress which is 2.4 cm. The number of leaves of banana plantlets under drought stress is the same as banana plantlets under drought stress at 3 leaves. Banana plantlets under drought and salinity stress showed chlorosis and necrosis. Salinity stress has a lower fresh weight compared to drought stress and without stress which is 2133 mg. Banana plantlets under drought stress had chlorophyll a 7 mg/L, chlorophyll b 14.34 mg/L, and total chlorophyll 21.7 mg/L. Banana plantlets under salinity stress contained chlorophyll a 7.33 mg/L, chlorophyll b 14.66 mg/L, and total chlorophyll 22 mg/L. Chlorophyll content in banana plantlets under drought and salinity stress was lower than in banana plantlets without stress. The expression of MaPSAL, MaPYROXYD1, and MaLHCA1 genes were down-regulated under drought and salinity stress. The MaFBA6 gene expression was up-regulated under drought and salinity stress. The gene expression of MaLHCA1 and MaPSAL under salinity stress showed lower than those under drought stress. The gene expression of MaFBA6 under salinity stress showed higher than those under drought stress. In this study, drought and salinity stresses decreased height, number of leaves, fresh weight, and chlorophyll contents of banana plantlets, decreased the expression of MaPSAL, MaPYROD1, MaLHCA1 genes and increased the expression of MaFBA6 genes in banana plantlets.