Effects of auxin (indole-3-butyric acid) on growth characteristics, lignification, and expression profiles of genes involved in lignin biosynthesis in carrot taproot

Abstract

Carrot is an important root vegetable crop abundant in bioactive compounds including carotenoids, vitamins, and dietary fibers. Carrot intake and its products are gradually growing owing to its high antioxidant activity. Auxins are a class of plant hormones that control many processes of plant growth and development. Yet, the effects of exogenous application of auxin on lignin biosynthesis and gene expression profiles of lignin-related genes in carrot taproot are still unclear. In order to investigate the effect of exogenous indole-3-butyric acid (IBA) on lignin-related gene profiles, lignin accumulation, anatomical structures and morphological characteristics in carrot taproots, carrots were treated with different concentrations of IBA (0, 50, 100, and 150 µM). The results showed that IBA application significantly improved the growth parameters of carrot. The 100 or 150 µM IBA treatment increased the number and area of xylem vessels, whereas transcript levels of lignin-related genes were restricted, resulting in a decline in lignin content in carrot taproots. The results indicate that taproot development and lignin accumulation may be influenced by the auxin levels within carrot plants.

Transcriptome Analysis Reveals a Gene Expression Pattern That Contributes to Sugarcane Bud Propagation Induced by Indole-3-Butyric Acid

“…Subsequently, three plant growth hormones like IAA, ABA, and GA 3 accumulated significantly ( p < 0.05) higher in 100 ppm concentration than control. These results are supported by several previous reports that discussed the efficacy of IBA in inducing the plant growth parameters, such as length, root weight, and leaves diameter, in different plants like strawberry and carrot plants ( Hossain and Gony, 2020 ; Khadr et al, 2020 ). Auxin influence many plant growth regulating functions during developmental processes, such as cell division, elongation, and differentiation ( Swarup et al, 2002 ; Yang et al, 2021 ; Xiong et al, 2022 ).…”

“…Bud sprouting is a critical phenomenon of the sugarcane plant that allows the development of adventitious roots (AR) during rooting. Phytohormones like IBA and Auxin are the major drivers in AR developments that regulate biological, cellular, and molecular functions ( Vidoz et al, 2010 ; An et al, 2020 ; Khadr et al, 2020 ; Li et al, 2020 ). During plant rooting, IAA played a significant role at the stage of root primordia formation ( Li et al, 2020 ; Xiong et al, 2022 ).…”

“…There have been many studies where scientists have used indole-3-butyric acid (IBA) and indole 3-acetic acid (IAA) to study in vitro the role of these hormones in inducing the roots ( Ludwig-Muller et al, 2005 ; Rout, 2006 ; Pacurar et al, 2014 ). IAA and IBA have been seen to induce adventitious root formation in mung bean ( Li et al, 2016a ), lotus ( Libao et al, 2018 ), tea ( Wei et al, 2014 ), sugarcanes ( Li et al, 2020 ), strawberry ( Hossain and Gony, 2020 ), carrot taproot ( Khadr et al, 2020 ), Arabidopsis ( Yang et al, 2021 ), and Euryodendron excelsum HT ( Xiong et al, 2022 ). Studies have shown that genes expressed predominantly on IBA treatment are involved in cell replication and weakening ( Brinker et al, 2004 ).…”

Lignin Synthesis, Affected by Sucrose in Lotus (Nelumbo nucifera) Seedlings, Was Involved in Regulation of Root Formation in the Arabidopsis thanliana

“…This phenomenon has also been identified in carrot taproots. Lignin accumulation decreases after the application of exogenous IBA, which results in an increase in root length [36]. Lignin metabolism originates from the phenylpropanoid pathway and participates in various biological processes during plant growth [37,38].…”

NnLAC17, a Gene Related to Lignin Synthesis, is Involved in Adventitious Root Formation in the Seedlings of Lotus (Nelumbo Nucifera Gaertn)

“…This phenomenon has also been identi ed in carrot taproots. Lignin accumulation is decreased after the application of exogenous IBA, which results in an increase in root length [40]. Lignin metabolism originates from the phenylpropanoid pathway and participates in various biological processes during plant growth [41,42].…”