Not so green as they’re cabbage looking

Not so mellow yellow There have been some very inter­est­ing papers pub­lished recently on how plants with­stand dis­eases. Plants see­ingly lack the soph­ist­ic­ated immune sys­tem of mamals, so dis­cov­er­ies of how they use the genes they have is noteworthy.


The fact that single immune recept­ors con­fer­ring mul­tiple res­ist­ances to taxo­nom­ic­ally unre­lated patho­gens may not be excep­tional gives plant breed­ers a strong incent­ive to identify and to use com­mon vir­ulence tar­gets as leads to dis­cover broad-specificity res­ist­ance genes:
Dual dis­ease res­ist­ance medi­ated by the immune receptor Cf-2 in tomato requires a com­mon vir­ulence tar­get of a fungus and a nem­at­ode. PNAS USA 06 June 2012 doi: 10.1073/pnas.1202867109 Plants lack the seem­ingly unlim­ited receptor diversity of a somatic adapt­ive immune sys­tem as found in ver­teb­rates and rely on only a rel­at­ively small set of innate immune recept­ors to res­ist a myriad of patho­gens. Here, we show that disease-resistant tomato plants use an effi­cient mech­an­ism to lever­age the lim­ited non­self recog­ni­tion capa­city of their innate immune sys­tem. We found that the extra­cel­lu­lar plant immune receptor pro­tein Cf-2 of the red cur­rant tomato (Solanum pimp­inel­li­fo­lium) has acquired dual res­ist­ance spe­cificity by sens­ing per­turb­a­tions in a com­mon vir­ulence tar­get of two inde­pend­ently evolved effect­ors of a fungus and a nem­at­ode. The Cf-2 pro­tein, ori­gin­ally iden­ti­fied as a mono­spe­cific immune receptor for the leaf mold fungus Cladosporium ful­vum, also medi­ates dis­ease res­ist­ance to the root para­sitic nem­at­ode Globodera rostochi­en­sis patho­type Ro1-Mierenbos. The Cf-2–mediated dual res­ist­ance is triggered by effector-induced per­turb­a­tions of the apo­plastic Rcr3pim pro­tein of S. pimp­inel­li­fo­lium. Binding of the venom allergen-like effector pro­tein Gr-VAP1 of G. rostochi­en­sis to Rcr3pim per­turbs the act­ive site of this papain-like cysteine pro­tease. In the absence of the Cf-2 receptor, Rcr3pim increases the sus­cept­ib­il­ity of tomato plants to G. rostochi­en­sis, thus show­ing its role as a vir­ulence tar­get of these nem­at­odes. Furthermore, both nem­at­ode infec­tion and tran­si­ent expres­sion of Gr-VAP1 in tomato plants har­bor­ing Cf-2 and Rcr3pim trig­ger a defense-related pro­grammed cell death in plant cells. Our data demon­strate that mon­it­or­ing host pro­teins tar­geted by mul­tiple patho­gens broadens the spec­trum of dis­ease res­ist­ances medi­ated by single plant immune receptors.

And there is also the recent work show­ing that plants can pass acquired defenses against pests and patho­gens on to their off­spring: Memory Tools for Plants — how plants pass defenses to off­spring through a com­plex molecu­lar network


Plants are clearly a lot smarter than many people give them credit for. The ques­tion is, are we smart enough to use these new dis­cov­er­ies to help feed ourselves in the future?


Ann Bot is a gestalt entity who works in the office for the Annals of Botany.