Increased resistance to a generalist herbivore in a salinity-stressed non-halophytic plant

Abstract

During their life, plants face multiple stresses. However, studies on one stress factor have typically neglected possible interactions with other factors. We demonstrated that salt stress in Indian mustard (a plant species not adapted to salinity) lessens the effect of herbivory on plant mass, and increases the plants' constitutive resistance to herbivores. Changes in the plants associated with increased salt that help to explain the mitigation of herbivore effects include decreased protein and macronutrient content. Plants exposed to herbivore damage were also less negatively affected by salt exposure, possibly due to their ability to maintain higher levels of transpiration.

Contrasts among cationic phytochemical landscapes in the southern United States

“…Whether these stoichiometric patterns hold across other micronutrients and nonessential elements across plant taxa and different habitats remains unquantified. (Boggs & Dau, 2004;Bravo et al, 2010;Burger & Gochfeld, 2003;Clay et al, 2017;Holdø et al, 2002), whereas high levels of plant Na concentrations have generated unique herbivore adaptations to prevent salt-induced stress encountered in some halophytic plant taxa that accumulate Na in plant tissues to evade herbivory (Kenagy, 1973;Renault et al, 2016). Yet, the mechanisms by which Na variation influences animal behavior across natural settings remain incompletely studied, especially when considering herbivorous species with large ranges.…”

Herbivore exposure alters ion fluxes and improves salt tolerance in a desert shrub

“…As salt stress and insect threats are coexisting factors that can hinder plant growth and productivity, we believe that it would be interesting to decipher the mechanisms by which plants respond to the combination of herbivory and salt stresses. Although crosstalk between the plant responses to these stresses has been implied in previous studies (Dinh et al, ; Renault et al, ; Vos et al, ), the physiological mechanisms involved are poorly understood and additional studies are needed.…”

“…As salt stress and insect threats are coexisting factors that can hinder plant growth and productivity, we believe that it would be interesting to decipher the mechanisms by which plants respond to the combination of herbivory and salt stresses. Although crosstalk between the plant responses to these stresses has been implied in previous studies (Dinh et al, 2013;Renault et al, 2016;Vos et al, F I G U R E 6 effects of NaCl on the transient Ca 2+ flux in root cells treated with eosin B, MnCl 2 /carbonyl cyanide 3-chlorophenylhydrazone (CCCP), verapamil, or ruthenium red, with or without herbivore pretreatment. Sevenday-old Ammopiptanthus nanus seedlings were or were not (control) subjected to herbivore feeding for 24 hr, after which, the seedling roots were left untreated or treated with eosin B (10 μM, a), MnCl 2 / CCCP (0.4 mM and 20 μM, c), verapamil (Ver; 10 μM, e), or ruthenium red (RuRed; 200 μM, g) for 30 min.…”

“…In tomato ( Solanum lycopersicum ), salt stress activates the expression of LOX, which is associated with the JA‐signalling pathway and the insect defence response and leading to accumulation of protease inhibitors in a JA‐dependent manner (Dombrowski, ). Indian mustard ( Brassica juncea ) resistance to Trichoplusia ni (cabbage looper) is increased by 36% under 100‐mM salt stress as a result of changes in its nutrient distribution (Renault, Wolfe, Markham, & Avila‐Sakar, ). Herbivore can also lead to elevation of the cytosolic Ca 2+ concentration ([Ca 2+ ] cyt ) as well as reactive oxygen species generation/accumulation (Maffei, Mithofer, & Boland, ; Zebelo & Maffei, ; Zebelo & Maffei, ), in addition to increased JA and ABA levels (Arimura et al, ; Kerchev et al, ), all of which protect against salt stress.…”

“…In tomato (Solanum lycopersicum), salt stress activates the expression of LOX, which is associated with the JA-signalling pathway and the insect defence response and leading to accumulation of protease inhibitors in a JAdependent manner (Dombrowski, 2003). Indian mustard (Brassica juncea) resistance to Trichoplusia ni (cabbage looper) is increased by 36% under 100-mM salt stress as a result of changes in its nutrient distribution (Renault, Wolfe, Markham, & Avila-Sakar, 2016).…”