Transgenic salt tolerance

Over 6% of the worlds total land area is naturally salt-affected and even more is becoming so as a consequence of mismanaged agricultural practices like land clearing, improper irrigation etc. Salt stress affects plants not only by causing water shortage but also through toxicity of Na+ and Cl ions as well as shortage of K+, Ca2+ and NO3. In a transgenic line of canola (Brassica napus), Liang-ju Wang and co-workers from Nanjing Agricultural University in China seems to have solved at least some of the problems. They used a light-induced Yhem1 gene encoding aminolevulinate synthase which is crucial for biosynthesis of 5-aminolevulinate (5-ALA). This compound has previously been shown to confer increased salt tolerance. Transgenic Yhem1-canola yielded more than three times more seeds than wildtype plants when grown under high-salt conditions and also accumulated more shoot and root biomass. Short-term experiments revealed that this was probably due to higher expression of the gene encoding Rubisco small subunit as well as increased diurnal photosynthetic rates in transgenic plants. Cl levels in leaves was significantly reduced in the transgenic plants and so was K+ and several other ions, while Fe accumulation was improved.

Read full article here: Sun et al (June 2015) Physiologia Plantarum 154: 223