Document Type : Research paper
Authors
1 Biotechnology and Molecular Genetic in Horticultural Products, University of Hormozgan, Bandar Abbas, Iran
2 Horticultural Science Department, Agriculture and Natural Resources College, University of Hormozgan, Bandar Abbas, Iran
3 Plant Protection Research Department, Hormozgan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Bandar Abbas, Iran
4 Department of Natural Resources Researches, Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Bandar Abbas, Iran
Abstract
Bacterial endophytes grow symbiotically inside plants and improve the growth of their hosts. We evaluated the effects of inoculating macroalgae bacterial endophytes, introduced formerly by our group, Bacillus aquimaris strain OD14, B. megaterium strain AM25, B. zhangzhouensis strain Tv91C, individually and in combination with each other on the reactive oxygen species (ROS) of scavenging and antioxidant functions, as well as growth characteristics of Mexican lime seedlings under salinity stress. Accordingly, Mexican lime (Citrus aurant-ifolia Swingle.) seedlings were subjected to four salinity levels, i.e. 0, 2000, 4000 and 6000 µs cm-1 in the presence or absence of bacterial endophytes. The results indicated that salinity stress significantly reduced growth, chlorophyll, and carotenoid content of plants lacking endophytes. Combinatory applications with bacterial endophytes significantly improved the above-mentioned parameters under salinity stress. Lipid peroxidation levels were significantly reduced in plants inoculated with bacterial endophytes. Salinity stress significantly increased the activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR), peroxidase (POD), and catalase (CAT) in salinity conditions. Overall, the inoculation with bacterial endophytes improved salinity tolerance and reduced the accumulation of ROS by increasing their scavenging via an enhanced redox state of glutathione and more effective antioxidant enzyme activities.
Keywords
)