plants growth while only three compound indole, 1-hexanol, and pentadecane
stimulated plant growth. Cocultivation ofA. thalianawithS. odoriferain divided
Petri dishes, which only let volatiles to diffuse from one side of the plate to the
other, resulted in dramatic growth inhibition of plants (Kai et al. 2010 ; Blom et al.
2011 ; Weise et al. 2014 ). Groenhagen et al. ( 2013 ) in their study compared the
effect of volatiles produced by threeBurkholderiastrains isolated from clinical
environment, pea rhizosphere, and maize roots. Exposure ofArabidopsis thaliana
plants to these volatiles resulted in significant increase in biomass, as well as growth
inhibition ofRhizoctonia solaniandAlternaria alternata. Also, volatile profiles of
these strains were found to be similar, and dimethyl disulfide was the most abun-
dant compound and sulfur compounds, ketones, aromatic compounds were other
significant components. This indicates that like their rhizospheric counterparts
endophytic strains are also capable of producing the similar volatiles and this can be
further explored in many other important species.
Application of dimethyl disulfide (DMDS) produced by aBacillus cereusstrain
significantly protected tobacco and corn plants against gray moldBotrytis cinerea
and southern corn leaf blightCochliobolus heterostrophus, respectively. It also
reduced the expression ofNicotiana attenuatasulfur assimilation genes, methionine
biosynthesis, and recycling (Huang et al. 2012 ). Acetoin and 2,3-butanediol
(2,3-BD) were frequently released from strains ofBacillus subtilisandB. amy-
loliquefaciensand were found to raise the total leaf surface area and induced
systemic resistance (ISR) ofArabidopsis thaliana(Ryu et al. 2003 ; Rudrappa et al.
2010 ). The study of D’Alessandro et al. ( 2014 ) revealed that production of 2,3-BD
byE. aerogenesrendered corn plants more resistant against the northern corn leaf
blight fungusSetosphaeria turcica. A large number of volatile produced by lemon
rhizobacteria is benzaldehyde, tridecanal, acetophenone, tetradecanal, and
6,10,14-trimethyl 2 pentadecanone have differential effects onArabidopsisroots is
correlated to the type and quantity of compounds produced by the bacteria
(Gutierrez-Luna et al. 2010 ). Similarly, 3-exanone produced by Burkholderia
ambifariasignificantly enhancedArabidopsisbiomass, as did acetophenone and
DMDS produced by lemon rhizobacteria and Bacillus cereus, respectively
(Groenhagen et al. 2013 ).
11.5.2 MVOC in Bacterial–Bacterial Interactions
Very scanty information is available about the nature of volatiles in bacterial–
bacterial communication, what is known till yet is briefly described here. The
communication may be stimulatory and inhibitory depending upon the one species
exerts an effect on other species. The stimulating effect of volatile compound
produced byCollimonas pratensisandSerratia plymuthicaobserved on the growth
ofPseudomonasfluorescens. The unique volatiles produced by the both bacterial
strains were benzonitrile, methyl thiocyanate, S-methyl thioacetate, and DMDS.
A blend of volatiles emitted by four bacteria namely,Paenibacillussp.,Pedobacter
244 D. Chandra et al.