A carrot somatic embryo mutant is rescued by chitinase.

Abstract

At the nonpermissive temperature, somatic embryogenesis of the temperature-sensitive (ts) carrot ceii mutant tsll does not proceed beyond the globular stage. This developmental arrest can be lifted by the addition of proteins secreted by wild-type cells to the culture medium. From this mixture of secreted proteins, a 32-kD glycoprotein, designated extracellular protein 3 (EP3), that allows completion of somatic embryo development in tsll at the nonpermissive temperature was purified. On the basis of peptide sequences and biochemicai characterization, EP3 was identified as a glycosylated acidic endochitinase. The addition of the 32-kD endochitinase to tsll embryo cultures at the nonpermissive temperature appeared to promote the formation of a correctly formed embryo protoderm. These results imply that a glycosylated acidic endochitinase has an important function in early plant somatic embryo development.

Sinorhizobium meliloti-induced chitinase gene expression in Medicago truncatula ecotype R108-1: a comparison between symbiosis-specific class�V and defence-related class�IV chitinases

“…Its symbiosis-specific induction and its responsiveness to Nod factors suggest a function during establishment of the nodule symbiosis. A role of chitinases in developmental processes is known from somatic embryo formation of carrot cells (de Jong et al 1992). Recent findings indicate that N-acetylglucosamine-containing arabinogalactan proteins of carrot cells are sensitive to chitinase cleavage and that the chitinase-modified proteins reinitiate cell division of non-dividing protoplasts (van Hengel et al 2001).…”

“…Thus, it has been proposed that cleavage of Nod factors is necessary to limit the amount of active Nod factors after their perception by the host plant (Staehelin et al 1995;Goormachtig et al 1998). Chitinases can also be directly involved in processes related to plant development by modifying extracellular N-acetylglucosaminecontaining arabinogalactan proteins (De Jong et al 1992;van Hengel et al 2001). In addition to these enzymatically active chitinases, a putative receptor kinase with a C-terminal class V chitinase domain and chitinase homologs without catalytic activity have been identified (Perlick et al 1996;Goormachtig et al 2001).…”

Transcriptome analysis for discovering candidate genes involve in embryogenesis in coconut (Cocos nucifera L.) through 454 pyrosequencing

“…Chitinases affect the early phases of embryo development and it could rescue somatic embryo development in mutant lines (De Jong et al, 1992), play a crucial role in embryogenesis by exhibiting higher expression mainly in transcriptome analysis in different species [e.g. Cyclamen persicum (Rensing et al, 2005); oil palm (Ho et al, 2007) .…”

The role of chitinases and glucanases in somatic embryogenesis of black pine and hybrid firs

“…Chitinases, glucanases [1], peroxidases [2], lipid transferases [3], and arabinogalactan proteins [4] are the most studied extracellular proteins. Chitinases, glucanases and peroxidases are pathogenesis related (PR) proteins, which play an important role in plants against different stress factors and pathogens.…”