Arbuscular mycorrhizal symbiosis influences strigolactone production under salinity and alleviates salt stress in lettuce plants

J Plant Physiol. 2013 Jan 1;170(1):47-55. doi: 10.1016/j.jplph.2012.08.020. Epub 2012 Oct 23.

Abstract

Arbuscular mycorrhizal (AM) symbiosis can alleviate salt stress in plants. However the intimate mechanisms involved, as well as the effect of salinity on the production of signalling molecules associated to the host plant-AM fungus interaction remains largely unknown. In the present work, we have investigated the effects of salinity on lettuce plant performance and production of strigolactones, and assessed its influence on mycorrhizal root colonization. Three different salt concentrations were applied to mycorrhizal and non-mycorrhizal plants, and their effects, over time, analyzed. Plant biomass, stomatal conductance, efficiency of photosystem II, as well as ABA content and strigolactone production were assessed. The expression of ABA biosynthesis genes was also analyzed. AM plants showed improved growth rates and a better performance of physiological parameters such as stomatal conductance and efficiency of photosystem II than non-mycorrhizal plants under salt stress since very early stages - 3 weeks - of plant colonization. Moreover, ABA levels were lower in those plants, suggesting that they were less stressed than non-colonized plants. On the other hand, we show that both AM symbiosis and salinity influence strigolactone production, although in a different way in AM and non-AM plants. The results suggest that AM symbiosis alleviates salt stress by altering the hormonal profiles and affecting plant physiology in the host plant. Moreover, a correlation between strigolactone production, ABA content, AM root colonization and salinity level is shown. We propose here that under these unfavourable conditions, plants increase strigolactone production in order to promote symbiosis establishment to cope with salt stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / genetics
  • Abscisic Acid / metabolism*
  • Biomass
  • Gene Expression Regulation, Plant
  • Germination
  • Glomeromycota / growth & development
  • Glomeromycota / physiology*
  • Lactones / metabolism*
  • Lactuca / drug effects
  • Lactuca / metabolism
  • Lactuca / microbiology*
  • Lactuca / physiology
  • Mycorrhizae / growth & development
  • Mycorrhizae / physiology*
  • Photosystem II Protein Complex / physiology
  • Plant Roots / drug effects
  • Plant Roots / metabolism
  • Plant Roots / microbiology
  • Plant Roots / physiology
  • Plant Transpiration
  • Salinity
  • Seeds / drug effects
  • Seeds / metabolism
  • Seeds / microbiology
  • Seeds / physiology
  • Sodium Chloride / pharmacology*
  • Stress, Physiological
  • Symbiosis
  • Time Factors

Substances

  • Lactones
  • Photosystem II Protein Complex
  • Sodium Chloride
  • Abscisic Acid