TTG1-mediated flavonols biosynthesis alleviates root growth inhibition in response to ABA

Abstract

Our results demonstrate that the flavonoids biosynthetic pathway can be effectively manipulated to confer enhanced plant root growth under water-stress conditions. Abscisic acid (ABA) is one of most important phytohormones. It functions in various processes during the plant lifecycle. Previous studies indicate that ABA has a negative effect on root growth and branching. Auxin is another key plant growth regulator that plays an essential role in plant growth and development. In contrast to ABA, auxin is a positive regulator of root growth and development at low concentrations. This study was performed to help understand whether flavonoids can suppress the effect of ABA on lateral root growth. The recessive TRANSPARENT TESTA GLABRA 1 (ttg1) mutant was characterized on ABA and sucrose treatments. It was determined that auxin mobilization could be altered by modifying flavonoids biosynthesis, which resulted in alterations of root architecture in response to ABA treatment. Moreover, transgenic TTG1-overexpression (TTG1-OX) seedlings exhibited enhanced root length and lateral root number compared to wild-type seedlings grown under normal or stress conditions. Genetic manipulation of the flavonoids biosynthetic pathway could therefore be employed successfully for the improvement of plant root systems by overcoming the inhibition of ABA and some abiotic stresses.

Genome‐wide association implicates numerous genes underlying ecological trait variation in natural populations of Populus trichocarpa

“…Both TTG1 and ANAC062 are transcription factors associated with stress responses. TTG1 affects many plant processes, including flavonoid biosynthesis, response to abscisic acid and root growth in relation to water stress in Arabidopsis (Nguyen et al, 2013). Likewise, ANAC062 is a membrane-associated stress response transcription factor in Arabidopsis and involved in abscisic acid response, cold stress and salinity tolerance (Seo & Park, 2010).…”

MYBD employed by HY5 increases anthocyanin accumulation via repression of MYBL2 in Arabidopsis

“…The expression levels of DFR and LDOX are regulated by the MBW (MYB/bHLH/WD40) complex, which consists of PRODUCTION OF ANTHOCYANIN PIGMENT 1 (PAP1), TRANSPARENT TESTA 8 (TT8) and TRANSPARENT TESTA GLABRA 1 (TTG1). PAP1 over‐expression increases DFR and LDOX transcript levels, whereas TTG1 over‐expressing transgenic plants do not show such responses (Borevitz et al ., ; Nguyen et al ., ). In addition to the activators, several negative regulators have been reported, such as MYB‐LIKE 2 (MYBL2) and SQUAMOSA PROMOTER BINDING PROTEIN‐LIKE 9 (SPL9), which interfere with formation of the MBW complex under various conditions (Dubos et al ., ; Matsui et al ., ; Gou et al ., ).…”

MYB-related transcription factors function as regulators of the circadian clock and anthocyanin biosynthesis in Arabidopsis

“…[18][19][20][21][22][23] In Arabidopsis, anthocyanin is only accumulated in the presence of light and this accumulation is promoted by different abiotic and biotic stress conditions such as cold, drought, and pathogen attack. 24,25 Almost 2 decades ago, the expressions of the genes involved in anthocyanin biosynthesis, such as CHALCONE SYNTHASE (CHS), CHALCONE ISOMERASE (CHI), and DIHYDROFLA-VONOL 4-REDUCTASE (DFR), were found to be regulated by a circadian rhythm.…”