Insights into the complicated networks contribute to adventitious rooting in transgenic MdWOX11 apple microshoots under nitrate treatments

Abstract

Adventitious root formation is a bottleneck for the mass propagation of microshoots, and nitrate is an essential nutrient regulating adventitious roots. WOX11 is involved in adventitious rooting. But the crosstalk between nitrate and WOX11 is completely unknown. In this study, MdWOX11 transgenic apple microshoots were grown on different nitrate treatments. Low nitrate promotes adventitious rooting in overexpressed microshoots more than wild type and RNA interference microshoots. In contrast, medium nitrate significantly inhibits it in overexpressed and RNA interference microshoots compared with wild type microshoots. Stem anatomy indicated that medium nitrate delays root primordia formation compared with low nitrate. Methyl jasmonate and zeatin riboside played positive and negative roles in adventitious rooting, respectively. Transcriptomic analysis was conducted to understand the molecular mechanisms behind the phenotypes better. Hormone signalling, sugar metabolism, nitrogen metabolism, cell cycle and root development pathway‐related genes were selected for their potential involvement in adventitious rooting. Results suggest that nitrogen signaling and MdWOX11 expression affect cytokinin accumulation and response to cytokinin through regulating the expression of genes related to cytokinin synthesis and transduction pathways, which ultimately affect adventitious rooting. This study provided important insights into the complicated networks involved in adventitious rooting in transgenic microshoots under nitrate treatments.

Transcription factor WOX11 modulates tolerance to cyst nematodes via adventitious lateral root formation

“…The estimated tolerance limit of 35S:WOX11-SRDX plants for cyst nematode infections was substantially lower than that of wild-type Col-0 plants. Others have shown that homologs of Arabidopsis WOX11 in rice, apple ( Malus ), and poplar enhance plant tolerance to abiotic stresses, such as drought and low nitrate conditions, by regulating adventitious lateral root formation ( Cheng et al 2016 ; Wang et al 2020 , 2021 ; Tahir et al 2022 ). Furthermore, WOX11 functions as a key regulator in the regeneration of primary roots after mechanical injury by inducing the formation of adventitious lateral roots at the cut site ( Sheng et al 2017 ).…”

The WOX Genes from the Intermediate Clade: Influence on the Somatic Embryogenesis in Medicago truncatula

“…So far, no data on WOX11 orthologs inducing SE or shoot regeneration have been published; however, they were shown to induce rooting and callus development [ 10 ]. On the other hand, MdWOX11 overexpression was shown to repress shoot regeneration in Malus domestica [ 7 ]. Since the expression of MtWOX11-1 increases during SE [ 13 ], it prompts finding the functions of this gene in this process, probably using mutant analysis.…”

“…Inhibition of the WOX11 pathway results in decreased rooting ability, whereas overexpression of WOX11 increases the ability of detached leaves to form roots [ 3 ]. The regulation of adventitious root initiation in leaves or in damaged roots by the WOX11 transcription factor or its orthologs has been studied in many species, including Panax [ 6 ], Malus [ 7 ], Populus [ 8 ], and Oryza [ 9 ] genera. In Panax ginseng adventitious roots branching regulation, WOX11 ortholog was shown to be a part of WOX-CLAVATA regulatory loop with the PgCLE45 gene.…”

WOX11-mediated adventitious lateral root formation modulates tolerance of Arabidopsis to cyst nematode infections

“…The estimated tolerance limit of 35S:WOX11-SRDX plants for cyst nematode infections was significantly lower than for wild-type Col-0 plants. Others have shown that homologs of Arabidopsis WOX11 in rice, apple, and poplar enhance plant tolerance to abiotic stresses, such as drought and low nitrate conditions, by regulating adventitious lateral root formation (Cheng et al, 2016;Wang et al, 2020;Wang et al, 2021;Tahir et al, 2022). Furthermore, WOX11 functions as a key regulator in the regeneration of primary roots after mechanical injury by inducing the formation of adventitious lateral roots at the cut site (Sheng et al, 2017).…”