Abstract
Pyridine 2,4-dicarboxylic acid is a structural analog of 2-oxoglutarate and is known to inhibit 2-oxoglutare-dependent dioxygenases. The effect of this inhibitor in tomato seedlings grown in MS media supplied with various concentrations of PDCA was investigated, resulting in shorter roots and hypocotyls in a dose-dependent manner. The partial inhibition of growth in roots was more drastic compared to hypocotyls and was attributed to a decrease in the elongation of root and hypocotyl cells. Concentrations of 100 and 250 μM of PDCA decreased hydroxyproline content in roots while only the 250 μM treatment reduced the hydroxyproline content in shoots. Seedlings treated with 100 μM PDCA exhibited enhanced growth of hypocotyl and cotyledon cells and higher hydroxyproline content resulting in cotyledons with greater surface area. However, no alterations in hypocotyl length were observed. Prolyl 4 hydroxylases (P4Hs) are involved in the O-glycosylation of AGPs and were also highly expressed during seedling growth. Moreover PDCA induced a decrease in the accumulation of HRGPs and particularly in AGPs-bound epitopes in a dose dependent-manner while more drastic reduction were observed in roots compared to shoots. In addition, bulged root epidermal cells were observed at the high concentration of 250 μM which is characteristic of root tissues with glycosylation defects. These results indicate that PDCA induced pleiotropic effects during seedling growth while further studies are required to better investigate the physiological significance of this 2-oxoglutarate analog. This pharmacological approach might be used as a tool to better understand the physiological significance of HRGPs and probably P4Hs in various growth and developmental programs in plants.
Highlights
The final plant organ size is controlled by environmental and genetic factors that coordinate cell expansion and division (Estevez et al, 2006; Gonzalez et al, 2010)
The hydroxyproline content in shoots and roots of 100 and 250 μM PDCA-treated seedlings was determined considering the inhibitory effect of 2-oxoglutarate analog on the activity of Prolyl 4 hydroxylases (P4Hs) in various plant species
The hypocotyl length was decreased by 1.5 cm at 250 μM of PDCA while no significant changes were observed at 100 μM (Figure 1C1)
Summary
The final plant organ size is controlled by environmental and genetic factors that coordinate cell expansion and division (Estevez et al, 2006; Gonzalez et al, 2010). The plant cell wall has a dominant role in cell growth through relaxation of the cross linking polymers, composition of new ones and rearrangement of its existing components (Tsukaya and Beemster, 2006) while cell growth is regulated by hormones and mainly ethylene and the ethylene-auxin crosstalk (Hu et al, 2006). Hydroxyproline rich glycoproteins (HRGPs) are structural and functional components of cell wall and their participation in cell division and enlargement is well-known (Kieliszewski and Lamport, 1994; Nothnagel, 1997; Seifert and Roberts, 2007). Among them pyridine 2,4-dicarboxylic acid (PDCA) suppressed ethylene production in carnation flowers and as a result delayed flower senescence (Vlad et al, 2010). It prolonged the shelf-life of a wide range of spray cut carnation flowers by enhancing flower opening in addition to retardation of senescence (Satoh et al, 2013, 2016; Sugiyama and Satoh, 2015)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
