Transcriptomic insights into the allelopathic effects of the garlic allelochemical diallyl disulfide on tomato roots

Abstract

Garlic is an allelopathic crop that can alleviate the obstacles to continuous cropping of vegetable crops. Diallyl disulfide (DADS), one of the most important allelochemicals in garlic, promotes tomato root growth. Therefore, the global transcriptome profiles of DADS-treated tomato roots over time were investigated to reveal the potential growth-promoting mechanisms. We detected 1828, 1296 and 1190 differentially expressed genes (DEGs) in the 4, 24 and 48 h samples, respectively. Most DEGs involved in assimilatory sulfate reduction and glutathione metabolism were up-regulated after short-term (4 h) DADS treatment. In addition, increased activity of defensive enzymes and up-regulation of six peroxidase genes were observed, suggesting that DADS could induce tomato resistance. In plant-pathogen interactions, DEGs related to calcium signaling were primarily inhibited, while those encoding pathogenesis-related proteins were primarily up-regulated. Although plant hormone synthesis and signal transduction were both significantly affected by DADS, the expression trends of the genes in these two pathways were conflicting. This research provides comprehensive information concerning the changes in the tomato root transcriptome affected by DADS and may help direct further studies on DADS-responsive genes to enhance the current understanding of the mechanisms by which DADS alleviates the obstacles to continuous cropping.

Small molecules below‐ground: the role of specialized metabolites in the rhizosphere

“…In a recent study, Cheng et al . () tested growth inhibitory effects of the sulfur‐containing volatile diallyl disulfide from garlic, which is known for its strong allelochemical potential. Diallyl disulfide either stimulated or inhibited the growth of tomato seedlings in a dose‐dependent manner by affecting cell division, phytohormone balance, and the expression of expansin genes.…”

“…Jassbi et al (2010) associated blends of monoterpene and sesquiterpene volatiles from roots of sagebrush (Artemisia tridentate) with phytotoxic effects on seedlings of the naturally co-occurring tobacco species, Nicotiana attenuata. In a recent study, Cheng et al (2016) tested growth inhibitory effects of the sulfur-containing volatile diallyl disulfide from garlic, which is known for its strong allelochemical potential. Diallyl disulfide either stimulated or inhibited the growth of tomato seedlings in a dosedependent manner by affecting cell division, phytohormone balance, and the expression of expansin genes.…”

Integration of transcriptome and proteome analyses reveal molecular mechanisms for formation of replant disease in Nelumbo nucifera

“…A consecutive monoculture induced the production of allelochemicals, and the allelochemicals released in the surroundings were able to activate ethylene signalling pathways, induce ROS accumulation and disrupt metabolic balance in high plants. 46,47 In addition, the role of ethylene and POD in the regulation of lignin was also indicated in transgenic tobacco. 48 Based on these results, we hypothesized that ROS and ethylene were released as responsive signals induced by a consecutive monoculture, which would stimulate the following processes, including the accumulation of lignin and avonoid, and the inhibition of antioxidant enzymes through DNA methylation.…”

A Two-Year Simulated Crop Rotation Confirmed the Differential Infestation of Broomrape Species in China Is Associated with Crop-Based Biostimulants

“…The capricious germination behavior of broomrape seeds to these extracts indicates that these crops contain certain biochemicals that are either very specific in their biological activities or bioactive in a certain concentration. Plant extracts may comprise of numerous bioactive compounds and their activity often depends on the concentration as shown in previous studies based on pepper extracts and garlic allelochemicals [21][22][23]. It is possible that pepper plant extracts may contain a group of biochemicals that counteract with each other's bioactivity and the concentration gradient may cause the bioactive potential to differentiate.…”

“…Chemical interaction may not entirely be entitled to demonstrate this situation as the possible contribution of certain physical factors, such as seed coat structure, which can alter the reception and perception of a certain biochemical or stimulus. It is possible that structural differences may result in the differential permeability for a certain chemical and therefore result in a different response from the subject seeds [23]. The sunflower broomrape seeds' structure seems to actively allow these crops' allelochemicals to permeate and facilitate the chemo-detection, resulting in successful seed germination.…”