The effect of β-aminobutyric acid (BABA) on root knot nematode and soft rot pathogen disease complexes in Solanum tuberosum plants

Abstract

The efficacy of three elicitors, DL-β-aminobutyric acid (BABA), Acibenzolar-S-methyl (Bion) and Messenger (Harpin) on potato plants inoculated with Meloidogyne incognita second stage juveniles (J2s) was investigated in this study. The efficacy of each elicitor was evaluated based on galling index, egg numbers, total root knot nematode (RKN) population numbers, number of juveniles and the percentage of females in respective extracted populations per treatment at 28 and 56 dpi. There was a significant decrease in galling indices of all treated compared to untreated control plants. The highest percentage reduction was observed for 20 mM BABA-treated plants (33%) followed by 5mM BABA (23%), 50mg/L Bion (18%), 100mg/L Bion (15%) and Messenger (8%). The number of eggs extracted from plants treated with 20mM BABA was significantly lower (66%) compared to untreated controls. Furthermore, treating plants with 20mM BABA decreased the total RKN population numbers by 55% whilst the decrease observed for 2 Bion and Messenger was between 24-39%. Of the three tested elicitors, 20mM BABA was found to be the most effective elicitor at both 28 and 56 dpi. Hence, it was selected for further testing against RKN and Pectobacterium carotovorum subsp. brasiliense (Pcb) disease complex. Efficacy was tested by comparing the colony forming units (cfu) of Pcb from treated and untreated control plants inoculated with M. incongita and Pcb simultaneously. The concentration of Pcb from untreated plants inoculated with both pathogens was significantly higher (3.3 × 10 3 cfu/ml) compared to their treated counterparts (8.71 × 10 2 cfu/ml). This suggests that BABA has the potential to decrease soft rot bacterial infections in RKN disease complexes by decreasing the rate of RKN infection. This is the first report where BABA is shown to decrease the infection rate of RKN as a primary causal agent in combination with a secondary pathogen.

Plant Resistance Inducers against Pathogens in Solanaceae Species—From Molecular Mechanisms to Field Application

“…The genus Nicotiana is both economically important and functions as models to explore basal biochemical and molecular functions of plants. Solanaceae has entered the genome era with potato being sequenced in 2011 [23], tomato in 2012 [24] and tobacco in 2014 [25]. There are several Solanaceae members in the 1001 genome project () and this will further increase our possibilities to understand immune responses in this plant family.…”

“…It should, however, be noted that several PRIs have been shown to affect both pests and non-pathogenic organisms. For example, β-aminobutyric acid (BABA) decreases root-knot nematode infections in potato [25]. Additionally, some PRIs have been reported to have an effect on abiotic stresses, e.g., BABA improved drought tolerance in potato [26].…”

β‐Aminobutyric acid induced phytotoxicity and effectiveness against nematode is stereomer‐specific and dose‐dependent in tomato

“…BABA‐IR was previously reported in tomato against B. cinerea (Luna et al, 2016), A. solani (Roylawar & Kamble, 2017) and against RKN such as M. incognita (Devran & Baysal, 2018), and M. javanica (Oka et al, 1999; Sahebani & Hadavi, 2009). Moreover, BABA was shown to induce resistance against RKN in other crops, such as in rice against Meloidogyne graminicola infection (Ji et al, 2015; Jisha & Puthur, 2016b), in potato against M. incognita (Mongae & Moleleki, 2015), and in cucumber against M. javanica (Sahebani et al, 2011). This phenotype was shown to be correlated with ABA‐signalling (Flors et al, 2008; Jakab et al, 2005; Ton & Mauch‐Mani, 2004), increased JA signalling, callose formation (Cohen et al, 2010; Hamiduzzaman et al, 2005; Ji et al, 2015), phenylalanine‐ammonia lyase activation (Baysal et al, 2005; Cohen & Gisi, 1994), and lignin accumulation (Cohen, 2001; Ji et al, 2015; Oka et al, 1999).…”