Effect of short- and long-time salt treatment on root traits and expression pattern of Atls۱ gene in barley (Hordeum vulgare L.)

Barley (Hordeum vulgare L.) as a salt-tolerant crop species has considerable economic importance in salinity-affected arid and semiarid regions of the world. In the present study, three barley genotypes (Sahara۳۷۷۱ and an Iranian advanced line as salt tolerant and Clipper as salt susceptible) were exposed to ۱۰۰ and ۲۰۰ mM NaCl at the seedling stage and non-NaCl treatment was used as check. The root samples were harvested ۲۴ hours, three days and three weeks after salt treatment in three replications. The root length and root fresh and dry weight were measured and expression pattern of Atls۱ gene was analyzed on root samples by quantitative Real-time-PCR. The effects of genotype and sampling time were significant for root characters and with the advancement of salt treatment duration, root length and root fresh and dry weight were significantly reduced. The expression of Atls۱ gene was significantly affected by NaCl level, genotype, sampling time and their interactions. In all three genotypes, with the increase of NaCl concentration, expression of Atls۱ gene was reduced. Under ۱۰۰ mM NaCl, mRNA level of Atls۱ was significantly decreased in Clipper as compared with the salt tolerant genotypes, Sahara۳۷۷۱ and Advanced line. In addition, long-term salt treatment (three weeks) significantly reduced the expression of Atls۱ in all three genotypes. Down-regulation of Atls۱ gene under long term salt treatment indicates that this gene may be involved in response to salinity stress at the beginning of salt stress.

Keywords:

Atls۱ gene , Barley , Real-Time PCR , Root growth , Salinity stress