title: Overexpression of AtNHX5 improves tolerance to both salt and drought stress in Broussonetia papyrifera (L.) Vent.
abstract: Paper mulberry (Broussonetia papyrifera L. Vent) is well known for its bark fibers, which are used for making paper, cloth, rope, etc. It was found that, in addition to its well-documented role in the enhancement of plant salt tolerance, overexpression of the Na+/H+ antiporter (AtNHX5) gene in paper mulberry plants showed high drought tolerance. After exposure to water deficiency and salt stress, the wild-type (WT) plants all died, while the AtNHX5-overexpressing plants remained alive under high salt stress, and had a higher survival rate (>66%) under drought stress. Measurements of ion levels indicated that Na+ and K+ contents were all higher in AtNHX5-overexpressing leaves than in WT leaves in high saline conditions. The AtNHX5 plants had higher leaf water content and leaf chlorophyll contents, accumulated more proline and soluble sugars, and had less membrane damage than the WT plants under water deficiency and high saline conditions. Taken together, the results indicate that the AtNHX5 gene could enhance the tolerance of paper mulberry plants to multiple environmental stresses by promoting the accumulation of more effective osmolytes (ions, soluble sugars, proline) to counter the osmotic stress caused by abiotic factors.
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, People's Republic of China.
authors.forename: Meiru
authors.initials: M
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Hongqing
authors.initials: H
authors.lastname: Li
authors.forename: Guojiang
authors.initials: G
authors.lastname: Wu
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics; D031623:Broussonetia / Q000235:genetics / Q000502:physiology*; D002241:Carbohydrates / Q000032:analysis; D002734:Chlorophyll / Q000032:analysis; D003681:Dehydration; D055864:Droughts; D015870:Gene Expression; D018515:Plant Leaves / Q000737:chemistry*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology; D011188:Potassium / Q000032:analysis; D011392:Proline / Q000378:metabolism; D055049:Salt Tolerance; D012964:Sodium / Q000032:analysis; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D002241:Carbohydrates; D017923:Sodium-Hydrogen Exchangers; D002734:Chlorophyll; D011392:Proline; D012964:Sodium; D011188:Potassium