Identification of Defense Compounds inBarbarea vulgarisagainst the HerbivorePhyllotreta nemorumby an Ecometabolomic Approach  

Abstract

Winter cress (Barbarea vulgaris) is resistant to a range of insect species. Some B. vulgaris genotypes are resistant, whereas others are susceptible, to herbivory by flea beetle larvae (Phyllotreta nemorum). Metabolites involved in resistance to herbivory by flea beetles were identified using an ecometabolomic approach. An F2 population representing the whole range from full susceptibility to full resistance to flea beetle larvae was generated by a cross between a susceptible and a resistant B. vulgaris plant. This F2 offspring was evaluated with a bioassay measuring the ability of susceptible flea beetle larvae to survive on each plant. Metabolites that correlated negatively with larvae survival were identified through correlation, cluster, and principal component analyses. Two main clusters of metabolites that correlate negatively with larvae survival were identified. Principal component analysis grouped resistant and susceptible plants as well as correlated metabolites. Known saponins, such as hederagenin cellobioside and oleanolic acid cellobioside, as well as two other saponins correlated significantly with plant resistance. This study shows the potential of metabolomics to identify bioactive compounds involved in plant defense.

UDP-Glycosyltransferases from the UGT73C Subfamily in Barbarea vulgaris Catalyze Sapogenin 3-O-Glucosylation in Saponin-Mediated Insect Resistance

“…The resistance of G-type B. vulgaris against herbivorous insects, such as P. xylostella and susceptible P. nemorum, has previously been shown to depend on the presence of saponins, and especially hederagenin and oleanolic acid cellobioside, which are absent in the susceptible P-type (Shinoda et al, 2002;Agerbirk et al, 2003a;Kuzina et al, 2009;Nielsen et al, 2010). Therefore, the synthesis of saponins was initially thought to be unique to the G-type.…”

“…Insect resistance of the one plant type, called G because it has glabrous leaves, correlates with the content of especially hederagenin cellobioside, oleanolic acid cellobioside, 4-epi-hederagenin cellobioside, and gypsogenin cellobioside (Shinoda et al, 2002;Agerbirk et al, 2003a;Kuzina et al, 2009;Fig. 1).…”

The Sg-1 Glycosyltransferase Locus Regulates Structural Diversity of Triterpenoid Saponins of Soybean

“…DDMP and group B saponins seem to be ubiquitously distributed with some variation in sugar chain structure at the C-3 position Takada et al, 2012), suggesting that DDMP and group B saponins might have a primary biological function in soybean. In general, saponins are considered to contribute to defense responses in plants because of their antimicrobial, antivirus, and anti-insect activities, although direct evidence in support of this notion is limited (Osbourn, 1996;Papadopoulou et al, 1999;Kuzina et al, 2009). Saponins also are thought to function as antioxidants by scavenging active oxygen species during growth and development (Tsujino et al, 1994;Yoshiki and Okubo, 1995).…”

Trends in the application of chemometrics to foodomics studies

“…The results of HCA are normally presented in dendrograms. The HCA method has been applied to complex data sets, such as LC-MS for studying a relationship between metabolites and plant's resistance against insects (KUZINA et al, 2009) and GC-MS data, where covariance of primary and secondary metabolites of seven rice cultivars have been explored (KIM et al, 2013). In addition, HCA is frequently used on spectroscopic data, such as Raman spectroscopy for classifi cation of citrus fruit (FENG et al, 2013) and FT-IR based molecular structural analysis of various feed and food mixture samples (ABEYSEKARA et al, 2013).…”