Salt-tolerant genes from halophytes are potential key players of salt tolerance in glycophytes

Abstract

Crop productivity strongly depends on several biotic and abiotic factors. Salinity is one of the most important abiotic factors, besides drought, extreme temperatures, light and metal stress. The enhanced burden of secondary salinization induced through anthropogenic activities increases pressure on glycophytic crop plants. The recent isolation and characterization of salt tolerance genes encoding signaling components from halophytes, which naturally grow in high salinity, has provided tools for the development of transgenic crop plants with improved salt tolerance and economically beneficial traits. In addition understanding of the differences between glycophytes and halophytes with respect to levels of salinity tolerance is also one of the prerequisite to achieve this goal. Based on the recent developments in mechanisms of salt tolerance in halophytes, we will explore the potential of introducing salt tolerance by choosing the available genes from both dicotyledonous and monocotyledonous halophytes, including the salt overly sensitive system (SOS)-related cation/proton antiporters of plasma (NHX/SOS1) and vacuolar membranes (NHX), energy-related pumps, such as plasma membrane and vacuolar H + adenosine triphosphatase (PM & V-H + ATPase), vacuolar H + pyrophosphatases (V-H + PPase) and potassium transporter genes. Various halophyte genes responsible for other processes, such as crosstalk signaling, osmotic solutes production and reactive oxygen species (ROS) suppression, which also enhance salt tolerance will be described. In addition, the transgenic overexpression of halophytic genes in crops (rice, peanut, finger millet, soybean, tomato, alfalfa, jatropha, etc.) will be discussed as a successful mechanism for the induction of salt tolerance. Moreover, the advances in genetic engineering technology for the production of genetically modified crops to achieve the improved salinity tolerance under field conditions will also be discussed. 2015 Elsevier B.V. All rights reserved.

Halophytes in biosaline agriculture: Mechanism, utilization, and value addition

“…First, potential genes from halophytes can be identified and used as candidates for improving salt tolerance in glycophytes. This can be achieved either by overexpression of identified gene of interest (reviewed in Himabindu et al, ) or by random approach wherein a cDNA library from halophyte is expressed in glycophyte and then cDNA inserts are identified in lines showing increased salt tolerance (Rigo et al, ). Second, halophyte cultivation is practiced for desalinization of degraded soils (Table ) and recovery of value‐added products (Table ).…”

Towards sustainable agriculture for the salt‐affected soil

“…Therefore, proline‐overproduction synthesis genes are a good way to enhance plant stress resistance. Our series of studies has shown that this way is applicable (Himabindu et al, ; Wang et al, ; Xu et al, ; Yan et al, ).…”

“…Currently, more than one third of the world's arable land is subjected to soil quality, and land degradation due to salt stress and agricultural yield has greatly decreased (Fan et al, ; Gao et al, ; Li et al, ; Tilman, Balzer, Hill, & Befort, ). Additionally, the salt‐affected area is increasing at a rate of 10% yearly because of high evaporation, low rainfall, inadequate irrigation, and other irrational anthropogenic activity (Himabindu et al, ; Liu et al, ; Mose et al, ). By 2050, the salinized area will exceed 50% of global arable land (Liu et al, ; Mao, Kang, et al, ; Mao, Zhang, et al, ; Sun et al, ).…”

“…So breeding salt-tolerant crops is vital to feed the increasing population (Yamaguchi & Blumwald, 2005). Now, genetic engineering with salt-tolerant genes especially from halophytes is selected as the better strategy to raise crop salt resistance (Himabindu et al, 2016;Mishra & Tanna, 2017;Nikalje, Srivastava, Pandey, & Suprasanna, 2018;Qi et al, 2018;Tang, Mu, Shao, Wang, & Brestic, 2014).…”

Wild halophytic species as forage sources: Key aspects for plant breeding

“…These adaptations are expressed in traits that can be used as potential selection criteria in breeding programmes for salinity tolerance. Several authors have suggested potential uses of various halophyte species, such as forage (Ashraf et al, 2006;Glenn et al, 2013;Panta et al, 2014;Rogers et al, 2005), oil production (Glenn et al, 2013;Weber, Ansari, Gul, & Khan, 2007), biodiesel production (McDowell Bomani, Bulzan, Centeno-Gomez, & Hendricks, 2009), human consumption (Barreira et al, 2017;Panta et al, 2014), soil phytoremediation (Shabala, 2013) and the use of known genes that improve the stress resistance of major crops (Ahanger et al, 2017;Himabindu et al, 2016). These studies reveal interesting possibilities for the use of these species for the development of technologies and salt-tolerant crops.…”