Location: Soil Management and Sugarbeet ResearchTitle: Transcriptional reprogramming and enhanced photosynthesis drive inducible salt tolerance in sugarcane mutant M4209
|NEGI, POOJA - Bhabha Atomic Research Centre|
|PANDEY, MANISH - Bhabha Atomic Research Centre|
|NIKAM, ASHOK - Vasantdada Sugar Institute|
|DEVARMUTH, RACHAYYA - Vasantdada Sugar Institute|
|SRIVASTAVA, ASHISH - Bhabha Atomic Research Centre|
|SUPRASANNA, PENNA - Bhabha Atomic Research Centre|
Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2020
Publication Date: 7/21/2020
Citation: Negi, P., Pandey, M., Dorn, K.M., Nikam, A., Devarmuth, R., Srivastava, A., Suprasanna, P. 2020. Transcriptional reprogramming and enhanced photosynthesis drive inducible salt tolerance in sugarcane mutant M4209. Journal of Experimental Botany. 71(19):6159-6173. https://doi.org/10.1093/jxb/eraa339.
Interpretive Summary: Sugarcane is an important cash crop that is grown throughout the world. In many regions where sugarcane is grown, soil salinity reduces crop quality including overall sugar yields. In this study, a new breeding line of sugarcane was characterized to understand how and why it exhibits tolerance to high salt concentrations. Grown in high salt conditions in the field, this new line named M4209, showed a 32% higher cane yield compared to its parent line Co86032, as well as exhibiting higher leaf biomass and other improved physiological characteristics. Next generation sequencing of RNA isolated from the M4209 and Co86032 lines grown under high salt conditions showed changes in gene expression for many proteins involved with photosynthesis. In the salt tolerant M4209 breeding line, the largest gene expression changes compared to the Co86032 parent were in genes that would indicate this new source of salt tolerance is linked to M4209 having a higher rate of photosynthesis. These findings represent a new source of germplasm for breeding salt tolerant sugarcane, as well as new potential molecular pathways that can be used to improve abiotic stress tolerance in crop plants.
Technical Abstract: Sugarcane (Saccharum officinarum L.) is a globally-cultivated cash crop whose yield is negatively affected by soil salinity. In the present study, we have investigated the molecular basis of inducible salt tolerance in M4209, a sugarcane mutant generated through radiation-induced mutagenesis. Under salt-contaminated fields, M4209 exhibited 32% higher cane yield as compared with its salt-sensitive parent Co86032. In continuation, M4209 displayed significantly higher leaf biomass in post-sprouting phenotyping, as compared with Co86032, under both 50 and 200 mM NaCl. This was concomitant with 1.9- (50 mM) and 1.6- (200 mM) fold higher K+/Na+ ratio and 4- (50 mM) and 40- (200 mM) fold higher glutathione reductase activity in M4209 as compared with that in Co86032, suggesting better ionic and redox homeostasis. Survey-based transcriptome profiling in M4209 indicated an extensive reprograming of photosynthesis and stress tolerance related genes under 50 mM NaCl stress. Ranking analysis identified PAL (Phenylalanine ammonia lyase), ATL (Acyl-transferase like gene) and SATA (Salt-activated transcriptional activator) as top-ranked genes associated with M4209’s salt tolerance. Additionally, M4209 exhibited 3-4-fold higher photosynthetic rate, as compared with Co86032 under NaCl stress conditions. Thus, the results highlighted the significance of transcriptional reprogramming coupled with photosynthetic efficiency for regulating salt tolerance in sugarcane.