Abstracts |
Arbuscular mycorrhiza (AM) is a widespread root endosymbiosis in which the fungal partner can gather soil nutrients, including phosphorus and nitrogen, through an extended mycelium network, and exchange them in plant roots for carbohydrates and lipids. AM can thus play an important role in crop nutrition in low fertilization sustainable agrosystems. Penetration of arbuscular mycorrhizal fungi (AMF) into roots relies on a plant symbiosis signaling pathway that can be activated by ‘symbiotic signals’ produced by AMF. The rice Lysin motif (LysM) receptor‐like kinase OsCERK1 is essential for activation of this signaling pathway and for root colonization by AMF. OsCERK1 is also essential for stimulation of root branching in the presence of AMF. This effect might be at least in part driven by the symbiotic signals that can induce root branching in grasses. Up to now, loss of function approaches have demonstrated the requirement of OsCERK1 for AM. In this issue of New Phytologist, Huang et al. (pp. 1762–1776) show that OsCERK1 allelic variation correlates with efficiency of AMF colonization and plant growth response to AMF. Using chromosome segment substitution lines (CSSLs) and transgenic plants, they have demonstrated that introgression, or addition, of an OsCERK1 allele from a wild rice species increases levels of AMF colonization. This study is interesting at several levels. First, it shows that sequence variation in a protein involved in perception of symbiotic signals can affect levels of AMF colonization; second, that increased levels of AMF colonization lead to increased growth responses in pots and increased yield in the field, and third that rice breeding might have counter‐selected efficient mycorrhizal interactions. |