Root endophytes modify the negative effects of chickpea on the emergence of durum wheat

Abstract

Secondary metabolite production in plants is influenced by biotic and abiotic environmental factors. We hypothesized that (1) resident root endophytes and (2) water limitation can modify the negative effects of chickpea on durum wheat. A Canadian prairie-resident root endosphere community was used to test these hypotheses. Microcosms were constructed with pasteurized field soil, inoculated or not with surface sterilized roots containing an endophytic community from the same soil, and one of four chickpea cultivars. Microcosms were maintained under conditions of water sufficiency or limitation (70% and 30% of field capacity) until chickpea plants reached maturity. The negative effects of the shoot and root tissues of these chickpea plants was then assessed in the same microcosm, using durum wheat as test plant. The impact of chickpea shoot tissues on durum wheat emergence was as negative as the impact of the positive control, black mustard, but chickpea roots had no effect. Initial introduction of root endophytes in the microcosms modified the pattern of durum wheat seedling emergence in chickpea tissues-amended soil, generally reducing the negative effect of chickpea, except for cultivar CDC Nika whose tissues impacted durum wheat maximum emergence rate more negatively in inoculated than non-inoculated microcosms. Water limitation had no effect on the negative properties of chickpea tissues. We conclude that unfavourable and favourable combinations of chickpea cultivars and resident root-associated microorganisms may explain at least partly, the erratic yield of wheat obtained after a chickpea crop.