Leucine-rich repeat transmembrane protein kinases (LRR-PK) regulate a wide range of developmental and defense related processes, such as hormone perception, host specific and non-host specific defense response, and wounding response [ 31].
Plant class III peroxidases are a key multifunctional enzyme family that is involved in diverse developmental and defense processes ([ 68, 71]).
Compelling evidence in the literature has revealed a fundamental role for members of the Arabidopsis LRRII-RLK subfamily as co-receptors for transducing developmental and defense signals [ 52- 54].
A canonical MAP kinase pathway minimally consists of a three tier linear phospho-transfer module namely MAPKKK-MAPKK-MAPK which connects diverse developmental and defense signals to the appropriate transcriptional response.
In addition, given its phylogenetic position as an early diverging land plant between green algae and flowering plants, it represents an interesting model plant to perform evolutionary studies of the role played by genes in developmental and defense processes.
The highly divergent C-terminal TAR regions of NAC proteins are thought to confer transcriptional activation of specific cellular functions including developmental and defense signaling pathways [ 19, 26, 27].
Because of its economic importance and biological role in various developmental and defense processes, the function of lignin biosynthesis related genes has been well studied in various plants [ 17, 18].
In plants since the first peptide hormone, systemin, is discovered twenty years ago [ 5], many small peptides have been identified, regulating developmental and defense processes including pollen tube guidance [ 6, 7], microspore-tapetum interaction [ 8, 9], stomata patterning [ 10- 13], cell proliferation [ 14, 15], stem cell homeostasis [ 16- 18] and wounding responses [ 5, 19, 20].
LRR domain containing proteins have been implicated in many developmental pathways and defense responses (as reviewed by [ 28]); this could imply that grafting with rootstocks triggered a defense response throughout the plant.
JA including Methyl Jasmonate (MeJA) and its free-acid form, JA, is an important signaling molecule for diverse developmental processes and defense responses (Kazan and Manners 2012).
