Zinc Induced Enzymatic Defense Mechanisms inRhizoctoniaRoot Rot Infected Clusterbean Seedlings

Abstract

This investigation was planned to determine the effect of different concentrations of zinc (Zn) on biochemical constituents of clusterbean, which play an important role in disease resistance mechanisms. Clusterbean seedlings were grown with 0, 10, or 20 mg Zn kg−1 soil treatments in earthen pots filled with 700 g inoculated soil. Soil was inoculated by pretreatment with 250 mg (wet weight) of Rhizoctonia inoculums per pot. A similar set was maintained in uninoculated soil. Root rot incidence decreased to 41 and 27 per cent with 10 and 20 mg Zn kg−1 soil treatments, respectively, as compared to 68 percent at control. Antioxidative enzyme activity (polyphenol oxidase, peroxidase, phenylalanine ammonia lyase, and tyrosine ammonia lyase) increased in inoculated seedlings and was increased further by 20 mg Zn kg−1 soil treatment. Antioxidative enzymes play an important role against fungal invasion, as peroxidase is involved in the formation of barrier via lignifications at the site of pathogen penetration. PAL and TAL play a key role in phenylpropanoid metabolism and could perform defense-related functions. Zn acts as a cofactor for these enzymes, so it can be concluded that Zn may be used as a soil-nutritive agent to increase resistance in plants against fungal diseases.

Using Zinc Oxide Nanoparticles to Improve the Color and Berry Quality of Table Grapes Cv. Crimson Seedless

“…Foliar spraying of ZnO NPs in our study increased PAL activity in Crimson grape leaves. Our results agreed with the findings of Wadhwa et al [51], who revealed that Zn acts as a co-factor for PAL enzyme activity. Additionally, Karimzadeh et al [36] found that the highest activity of the PAL enzyme was found when using 30 ppm nano-ZnO in flax plant.…”

“…Our results were consistent with Song et al [ 21 ], who mentioned that Zn treatments enhanced the accumulation of anthocyanins in berry skin, and Hashemi et al [ 56 ], who explained the role of ZnO nanoparticles in increasing anthocyanin production in soybean. Additionally, Wadhwa et al [ 51 ] mentioned that Zn served as a co-factor for PAL enzyme activity and Medda et al [ 12 ] advocated that Zn played a regulatory enzyme during fruit ripening for flavonoid biosynthesis.…”

Exogenous Application of Zinc to Mitigate the Salt Stress in Vigna radiata (L.) Wilczek—Evaluation of Physiological and Biochemical Processes

“…The present investigation revealed that the specific activity of TAL also increased with salt and Zn application ( Figure 8 B). Our results are in accordance with the findings of cluster bean where specific activity of TAL doubled after Zn treatment [ 98 ]. It is noteworthy to mention that Zn acts as a cofactor for PAL and TAL enzymes and therefore, these enzymes’ activities might have up-regulated after exogenous application of Zn.…”

Zinc thiazole enhances defense enzyme activities and increases pathogen resistance to Ralstonia solanacearum in peanut (Arachis hypogaea) under salt stress

“…Here, activities of PPO and PAL were also up-regulated by ZT in the salt-stressed seedlings after pathogen inoculation (Fig 5). Previous data also showed that Zn element can enhance PAL and PPO enzyme activities in Rhizoctonia infected clusterbean seedlings [29]. Our data suggest that ZT-enhanced pathogen resistance in salt-stressed peanuts can be partly attributed to its up-regulation of defense enzyme (e.g.…”

“…However, the direct defense mechanisms by which ZT improves pathogen resistance under salt stress are still elusive. In addition, previous data show that Zn is an indispensable element of the SOD enzyme [28] or activator of defense enzymes [29]. Thus, the activities of antioxidant (e.g.…”