First Report of Protective Activity of Paronychia argentea Extract against Tobacco Mosaic Virus Infection

Abstract

The widespread use of chemical control agents and pesticides for plant-pathogen control has caused many human health and environmental issues. Plant extracts and biocontrol agents have robust antimicrobial activity against different plant pathogens. However, their antiviral activities are still being investigated. In the present study, the methanol extract of Paronychia argentea was characterized and evaluated for its protective activity against the tobacco mosaic virus (TMV) infection in tomato plants under greenhouse conditions at 21 days post-inoculation. The results showed that the foliar application of P. argentea extract (10 µg/mL) enhanced tomato plant growth, resulting in significant increases in shoot and root parameters and total chlorophyll contents. Moreover, a significant reduction in TMV accumulation level in P. argentea-treated plants of 77.88% compared to non-treated plants was reported. Furthermore, induction of systemic resistance with significant elevation in production of antioxidant enzymes (PPO, CAT, and SOD) and transcriptional levels of the pathogenesis-related proteins (PR-1 and PR-7) and polyphenolic genes (CHS and HQT) were also observed. Out of 16 detected compounds, HPLC analysis revealed that the most abundant polyphenolic compounds found in P. argentea extract were gallic acid (5.36 µg/mL), kaempferol (7.39 µg/mL), quercetin (7.44 µg/mL), ellagic acid (7.89 µg/mL), myricetin (8.36 µg/mL), and ferulic acid (8.69 µg/mL). The findings suggest that the use of P. argentea extract as an effective and safe source for the production of bioactive compounds may offer a solution for a promising approach for the management of plant viral infections. To the best of our knowledge, this is the first report of the protective activity of P. argentea extract against plant viral diseases.

Trichoderma hamatum Strain Th23 Promotes Tomato Growth and Induces Systemic Resistance against Tobacco Mosaic Virus

“…Thus, the elevation of transcriptional expression of these genes demonstrates their antiviral role, implying that the tomato plant can utilize polyphenolic compounds as one of its defenses against viral infection and spread. In line with the obtained results, the increased expression levels of CHS and HQT resulted in the accumulation of polyphenolic compounds inside plant tissues, the development of SAR, and increased resistance against TMV infestation [21]. As a result, pretreating tomato plants with Th23 may result in an increase in numerous flavonoid compounds.…”

“…was associated with an increase in root length, shoot length, and dry weight compared to the control plants [ 9 , 54 , 55 , 56 ]. Generally, the severe morphological and physiological changes including mosaic symptoms that occur upon viral infection are linked to changes in chlorophyll content and result in reduced photosynthesis [ 21 , 57 ]. Thus, the changes in chlorophyll pigment content upon viral infection can be used to indicate the functional status of photosynthesis in plants [ 58 ].…”

“…Several reports have proposed that a convergent collection of PR proteins is responsible for SAR development and is effective in suppressing pathogen multiplication and/or dissemination [ 21 , 91 , 92 ]. For PR-1 , it was shown that the TMV treatment exhibited a significant decrease in PR-1 expression level by 0.77-fold lower than the control at p ≤ 0.05.…”

“…Furthermore, Singh et al [ 19 ] found that biotic inducers raised the levels of several PRs such as peroxidase and chitinase isozymes. The increase in PR-1 as a SA molecular marker gene is closely linked to the activation of salicylic acid (SA) during pathogen infection and a variety of physiological responses in plants in response to biotic stressors [ 20 , 21 ]. Polyphenolic substances are among the secondary metabolites that play a significant role in plant development, growth, and tolerance to biotic and abiotic stresses [ 22 ].…”

The Application of Pomegranate, Sugar Apple, and Eggplant Peel Extracts Suppresses Aspergillus flavus Growth and Aflatoxin B1 Biosynthesis Pathway

“…Currently, the use of plant-based natural antifungal agents is considered a beneficial and healthy practice in this regard [13,14]. Plant extracts could be employed as antimicrobial agents or for improved food storage and preservation due to their high activity, the simplicity of their production and utilization, their reliability, and their biocompatibility [15,16].…”