Leaf and root glucosinolate profiles of Chinese cabbage (Brassica rapa ssp. pekinensis) as a systemic response to methyl jasmonate and salicylic acid elicitation

Abstract

Zang et al. / J Zhejiang Univ-Sci B (Biomed & Biotechnol) 2015 16(8)Abstract: Glucosinolates (GSs) are an important group of defensive phytochemicals mainly found in Brassicaceae. Plant hormones jasmonic acid (JA) and salicylic acid (SA) are major regulators of plant response to pathogen attack. However, there is little information about the interactive effect of both elicitors on inducing GS biosynthesis in Chinese cabbage (Brassica rapa ssp. pekinensis). In this study, we applied different concentrations of methyl jasmonate (MeJA) and/or SA onto the leaf and root of Chinese cabbage to investigate the time-course interactive profiles of GSs. Regardless of the site of the elicitation and the concentrations of the elicitors, the roots accumulated much more GSs and were more sensitive and more rapidly responsive to the elicitors than leaves. Irrespective of the elicitation site, MeJA had a greater inducing and longer lasting effect on GS accumulation than SA. All three components of indole GS (IGS) were detected along with aliphatic and aromatic GSs. However, IGS was a major component of total GSs that accumulated rapidly in both root and leaf tissues in response to MeJA and SA elicitation. Neoglucobrassicin (neoGBC) did not respond to SA but to MeJA in leaf tissue, while it responded to both SA and MeJA in root tissue. Conversion of glucobrassicin (GBC) to neoGBC occurred at a steady rate over 3 d of elicitation. Increased accumulation of 4-methoxy glucobrassicin (4-MGBC) occurred only in the root irrespective of the type of elicitors and the site of elicitation. Thus, accumulation of IGS is a major metabolic hallmark of SA-and MeJA-mediated systemic response systems. SA exerted an antagonistic effect on the MeJA-induced root GSs irrespective of the site of elicitation. However, SA showed synergistic and antagonistic effects on the MeJA-induced leaf GSs when roots and leaves are elicitated for 3 d, respectively.

Possible Interactions between the Biosynthetic Pathways of Indole Glucosinolate and Auxin

“…In Brassica rapa , SA antagonistically affected methyl-JA induced GLS accumulation in the root regardless of the site of elicitation. Similar effect was found in the leaves when the roots were elicited, however, the effect was synergetic if the leaves were elicited ( Zang et al, 2015 ).…”

Biosynthesis and bioactivity of glucosinolates and their production in plant in vitro cultures

“…In fact, the levels of total glucosinolates found in 63 varieties of B. rapa from northwestern Spain evaluated at two different sites (Padilla et al 2007) were lower (34.5 and 26 lmol/g DW) than those found in B. rapa hairy root cultures elicited with 50 lM jasmonic acid (about 75 lmol/g DW, Kastell et al 2013a). Similarly, Zang et al (2015) showed that the maximal levels of total glucosinolates found in leaves of B. rapa ssp. Pekinensis elicited with 200 lM of methyl jasmonate were 62.12 ± 5.56 lmol/g DW while the levels found in roots were higher (114.05 lmol/g DW).…”

“…However, transgenic hairy root cultures which overexpressed CYP79B2 and CYP83B1 or CYP83B1, CYP79B2 and CYP79B3 accumulated high levels of 4-methoxy glucobrassicin (about 1.17 and 0.95 nmol/g FW, respectively) compared to non-transgenic hairy root cultures (0.5 nmol/g FW) ( Table 2). Another transgenic line transformed with CYP79B2, CYP79B3 and CYP83B1 genes also showed an increase in the levels of glucobrassicin being 1.5-fold greater than control lines (Zang et al 2009). Kastell et al (2015) also observed high levels of short-chain aliphatic and indole glucosinolates (about 3.5 and 9 lmol/g DW, respectively) in A. thaliana hairy root cultures with an additional expression of CYP79F1 (Table 2).…”

Exogenous Methyl Jasmonate and Salicylic Acid Induce Subspecies-Specific Patterns of Glucosinolate Accumulation and Gene Expression in Brassica oleracea L.

“…Exogenous application of jasmonic acid (JA) or salicylic acid (SA) is often used to mimic biotic stress. In notable number of studies, JA and SA applications have been shown to increase accumulation of beneficial biomolecules, including glucosinolates [21,22,23,24,25,26,27,28,29,30,31,32,33]. Methyl jasmonate (MeJA) can be utilized in fields for Brassica vegetable production to enhance human health-promoting glucosinolates and the market value of the products [25].…”