Analysis of salt-induced physiological and proline changes in 46 switchgrass (Panicum virgatum) lines indicates multiple response modes

• Published in: Plant physiology and biochemistry Vol. 105; no. C; pp. 203 - 212
• Main Authors: Kim, Jeongwoon, Liu, Yiming, Zhang, Xunzhong, Zhao, Bingyu, Childs, Kevin L.
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.08.2016; Elsevier
• Subjects: Cluster Analysis; Panicum - physiology; Panicum virgatum; Phenotype; Photosynthetic rate; Physiology; Principal Component Analysis; proline; Proline - drug effects; Proline - metabolism; Quantitative Trait, Heritable; Salt stress; Salt-Tolerance - drug effects; Sodium Chloride - pharmacology; Stress, Physiological - drug effects; Switchgrass; proline; Photosynthetic rate; Physiology; Salt stress; Switchgrass
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2016.04.020

Switchgrass (Panicum virgatum) is targeted as a biofuel feedstock species that may be grown on marginal lands including those with saline soils. Our study investigated salt stress responses in 46 switchgrass lines from the lowland and upland ecotypes by assessing physiological phenotypes and proline concentrations. Lowland switchgrass lines demonstrated less severe responses to salt stress than most upland switchgrass lines, but a number of upland lines performed as well as lowland individuals. Photosynthetic rate (Pn), the most important physiological trait measured, was reduced by salt treatment in all lines. Tolerant lines showed ∼50% reduction in Pn under salt stress, and sensitive lines exhibited ∼90% reduction in Pn after salt stress. Proline analysis showed the largest amount of variation under salt stress with some lines exhibiting minor increases in proline, but some salt-sensitive lines demonstrated more than 5000-fold increase in proline concentration in response to salt treatment. Clustering of salt-stress phenotypic responses revealed five groups of switchgrass. Lowland lines were present in two of the phenotypic clusters, but upland lines were found in all five of the phenotypic clusters. These results suggest that there are multiple modes of salt response in switchgrass including two distinct modes of salt tolerance. •Forty-six upland and lowland lines of switchgrass were screened for salt tolerance.•Lowland switchgrass lines were found to be the most salt tolerant.•Several upland switchgrass lines were also found to be salt tolerant.•Physiological and proline responses to salt stress suggest multiple modes of salt tolerance.