APYRASE1/2 mediate red light-induced de-etiolation growth in Arabidopsis seedlings

Abstract

In etiolated seedlings, red light (R) activates phytochrome and initiates signals that generate major changes at molecular and physiological levels. These changes include inhibition of hypocotyl growth and promotion of the growth of primary roots, apical hooks, and cotyledons. An earlier report showed that the sharp decrease in hypocotyl growth rapidly induced by R was accompanied by an equally rapid decrease in the transcript and protein levels of two closely related apyrases (nucleoside triphosphate-diphosphohydrolases) in Arabidopsis (Arabidopsis thaliana), APY1 and APY2, enzymes whose expression alters auxin transport and growth in seedlings. Here, we report that single knockouts of either apyrase inhibits R-induced promotion of the growth of primary roots, apical hooks, and cotyledons, and RNAi-induced suppression of APY1 expression in the background of apy2 inhibits R-induced apical hook opening. When R-irradiated primary roots and apical hook-cotyledons began to show a gradual increase in their growth relative to dark controls, they concurrently showed increased levels of apyrase protein, but in hook-cotyledon tissue, this occurred without parallel increases in their transcripts. In wild-type seedlings whose root growth is suppressed by the photosynthesis inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea, the R-induced increased APY expression in roots was also inhibited. In unirradiated plants, the constitutive expression of APY2 promoted both hook opening and changes in the transcript abundance of Small Auxin Upregulated RNA (SAUR), SAUR17 and SAUR50 that help mediate de-etiolation. These results provide evidence that the expression of APY1/APY2 is regulated by R and that APY1/APY2 participate in the signaling pathway by which phytochrome induces differential growth changes in different tissues of etiolated seedlings.

Genome-wide identification and analyses of ZmAPY genes reveal their roles involved in maize development and abiotic stress responses

“…Suppression of their expression affects root and shoot growth (Wu et al 2007). Additionally, APY1/APY2 also participate in the phytochrome-mediated signaling pathway that induces differential growth changes in etiolated seedling tissues (Weeraratne et al 2022). Another member of the APY gene family, APY7, acts as a negative regulator of cell growth.…”

Genome-wide identification and analyses of ZmAPY genes reveal their roles involved in maize development and abiotic stress responses

“…Suppression of their expression affects root and shoot growth (Wu et al 2007 ). Additionally, APY1 / APY2 also participate in the phytochrome-mediated signaling pathway that induces differential growth changes in etiolated seedling tissues (Weeraratne et al 2022 ). Another member of the APY gene family, APY7 , acts as a negative regulator of cell growth.…”

Overexpression of PagSTOMAGEN, a Positive Regulator of Stomatal Density, Promotes Vegetative Growth in Poplar

“…Photosynthesis is a prerequisite for biomass production [ 30 ], and is affected by a large number of key genes, such as the photosystem key factors PSAB [ 32 ], PSAN [ 33 ], and PSBX [ 34 ], as well as some important growth regulators, such as GRF5 [ 35 ], GNC [ 36 ], and PIFs [ 37 ]. Auxin-responsive factors, such as ARFs and SAUR -like auxin-responsive protein [ 38 , 39 , 40 ], are all differentially expressed when stimulated by auxin. Cytokinins are mainly affected by CKX family genes [ 41 ].…”