Expression Profiling of Candidate Genes in Sugar Beet Leaves Treated with Leonardite-Based Biostimulant

Abstract

Leonardite-based biostimulants are a large class of compounds, including humic acid substances. Foliar application of biostimulants at field level improves plant growth, yield and quality through metabolic changes and stimulation of plant proton pumps. The present study aimed at identifying optimum dosage of BLACKJAK, a humic acid-based substance, which is able to modify genes involved in sugar beet growth. Thirty-three genes belonging to various biochemical pathway categories were tested in leaves of treated sugar beet (Beta vulgaris L.) samples to assess gene expression profiling in response to BLACKJAK. Seedlings of a diploid and multigerm variety were grown in plastic pots and sprayed with two dilutions of BLACKJAK (dilution 1:500–1.0 mg C L−1 and dilution 1:1000–0.5 mg C L−1). Leaf samples were collected after 24, 48, and 72 h treatment with BLACKJAK for each dilution. RNA was extracted and the quantification of gene expression was performed while using an OpenArray platform. Results of analysis of variance demonstrated that, 15 genes out of a total of 33 genes tested with OpenArray qPCR were significantly affected by treatment and exposure time. Analysis for annotation of gene products and pathways revealed that genes belonging to the mitochondrial respiratory pathways, nitrogen and hormone metabolisms, and nutrient uptake were up-regulated in the BLACKJAK treated samples. Among the up-regulated genes, Bv_PHT2;1 and Bv_GLN1 expression exerted a 2-fold change in 1:1000 and 1:500 BLACKJAK concentrations. Overall, the gene expression data in the BLACKJAK treated leaves demonstrated the induction of plant growth–related genes that were contributed almost to amino acid and nitrogen metabolism, plant defense system, and plant growth.

Novel Effects of Leonardite-Based Applications on Sugar Beet

“…generally based on the already known activity of humic acids on plant growth and development (Canellas et al, 2015;Nardi et al, 2016;Barone et al, 2019;Hajizadeh et al, 2019). However, the aforementioned genes were tested only on plants grown in hydroponic conditions, showing significant variation compared to untreated samples after 24 h of treatment.…”

“…The molecular analysis conducted in this work was done to evaluate hormonal gene responses, induced by leaf application of leonardite. The analyzed gene, belonging to hormonal metabolism, was selected among a larger set of 53 genes related to leonardite treatment on sugar beet and more generally based on the already known activity of humic acids on plant growth and development ( Canellas et al, 2015 ; Nardi et al, 2016 ; Barone et al, 2019 ; Hajizadeh et al, 2019 ). However, the aforementioned genes were tested only on plants grown in hydroponic conditions, showing significant variation compared to untreated samples after 24 h of treatment.…”

Effect of Microalgal Extracts from Chlorella vulgaris and Scenedesmus quadricauda on Germination of Beta vulgaris Seeds

“…The sugar beet variety used in this study is the hybrid “Shannon” provided by the Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE) of the University of Padova (Italy) [ 40 ]. Seeds were soaked in 76% ethanol for 5 min, rinsed with sterilized water, and placed on distilled water moistened filter paper.…”

The preventive impact of vermicompost on bell pepper (Capsicum annuum L.) salinity resistance: An evaluation

“…Therefore, it may be viewed as an effectual protective element capable of reinforcing plant resistance against salt stress, whereby such modifications and their underpinning mechanisms can be attributed to VCL properties. Additionally, humic acid extraction from earthworm compost has been recorded to show auxin properties, while indole acetic acid can congregate by the supramolecular arrangement of humic acid (Hajizadeh et al, 2019). Despite certain works have noted abscisic acid to be present in vermicompost, Bulgari et al (2019b) have stated its level may be reduced by humic acids.…”

“…As a result, the parameters of nutrient uptake and efficiency and plant stress tolerance are enhanced, thus yielding in quality crops. Besides, such products are accessible across different types, whereby a majority of them consist of an intricate amalgamation of various active substances (Hajizadeh et al, 2019). In particular, vermicompost is a form of eco-friendly organic fertilizer generally manufactured by earthworm actions, namely via organic waste digestion.…”