The Nep1-like proteins - a growing family of microbial elicitors of plant necrosis

A novel family of microbial elicitors of plant necrosis has been identified. Designated Nep1-like proteins (NLPs), after the first family member isolated, they range from 24 to 26 kDa and are found in a variety of taxonomically unrelated micro-organ isms. These include several fungi and oomycetes, as well as Gram-positive and Gram-negative bacteria. Some NLPs induce a hypersensitive-like response in plants, although the basis for initiation of this response remains unclear. Similarly, the cellular role of such highly conserved proteins is undetermined. It is not clear whether the NLPs; are dedicated elicitors of plant defences or whether this induction occurs as a result of another activity.