Function identification of MdTIR1 in apple root growth benefited from the predicted MdPPI network

et al. 2021

Preprint

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SummaryFlavonoids are a class of polyphenol compounds that are widespread in plants. They play an important role in plant growth and development. In this study, we found a mutant strain of M. baccata with yellow leaves (YL). Transcriptome sequencing revealed that it exhibited significant changes in the flavonoid metabolism pathway, which screening revealed was associated with a glycosyltransferase gene, MD09G1064900 (MdGT1). Analysis of its spatiotemporal expression showed that MdGT1 was mainly expressed in the stem and leaves, it means that MdGT1 may have a functional role in these parts. Real-time PCR and HPLC showed that MdGT1 was significantly upregulated by anthocyanin and exhibited strong anthocyaninase activity in vitro, respectively. An MdGT1 plant expression vector was constructed and overexpressed in apple fruit callus, resulting in a significant decrease of anthocyanin. Phenotypic observation also revealed that the MdGT1-overexpressing lines exhibited worse growth than the wild type after NaCl treatment, while they grew better upon the addition of exogenous anthocyanins. Moreover, real-time PCR and physiological data showed that MdGT1 is involved in salt stress and closely related to antioxidant pathways. Electrophoretic mobility shift assays (EMSA) and yeast one-hybrid experiments also proved that the transcription factor MdMYB88 is an upstream regulatory factor of MdGT1. The sequencing results revealed an amino acid insertion in an MdMYB88 HTH domain (between 77-131 amino acids) in the YL mutant strain. In conclusion, we identified a new apple glycosyltransferase gene, MdGT1, which may affect the color of apple leaves by glycosylating anthocyanins, and be regulated by the upstream transcription factor MdMYB88.Significance statementThe glycosyltransferases and their physiological significance in apple are largely unknown. Here we revealed that the MdMYB88-regulated apple glycosyltransferase gene MdGT1 plays a crucial role in the color of apple leaves and enhances plant tolerance to salt by antioxidant pathways via anthocyanin metabolism.

Section: Methodsmentioning

confidence: 99%

Genome-wide analysis of the apple family 1 glycosyltransferases identified a flavonoid-modifying UGT, MdUGT83L3, which is targeted by MdMYB88 and contributes to stress adaptation

et al. 2021

Preprint

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“…In 1993, two Aux/IAA genes, PS‐IAA4/5 and PS‐IAA6 , were first isolated from pea ( Pisum sativum L.) (Oeller et al, 1993). Through homologous sequence alignment and plant genome sequencing, 29 Aux/IAAs were identified in Arabidopsis (Okushima et al, 2005), 31 in maize (Wang et al, 2010), 31 in rice ( Oryza sativa ) (Jain et al, 2006), 47 in apple ( Malus domestica ) (Liu et al, 2021), and so on. A typical Aux/IAA protein contains four domains, Domain I to Domain IV (Ma et al, 2018).…”

Section: Downstream Signaling and Responsesmentioning

confidence: 99%

Auxin signaling: Research advances over the past 30 years

Friml

et al. 2022

JIPB

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125

Auxin, one of the first identified and most widely studied phytohormones, has been and will remain a hot topic in plant biology. After more than a century of passionate exploration, the mysteries of its synthesis, transport, signaling, and metabolism have largely been unlocked. Due to the rapid development of new technologies, new methods, and new genetic materials, the study of auxin has entered the fast lane over the past 30 years. Here, we highlight advances in understanding auxin signaling, including auxin perception, rapid auxin responses, TRANSPORT INHIBITOR RESPONSE 1 and AUXIN SIGNALING F-boxes (TIR1/AFBs)-mediated transcriptional and non-transcriptional branches, and the epigenetic regulation of auxin signaling. We also focus on feedback inhibition mechanisms that prevent the over-amplification of auxin signals.In addition, we cover the TRANSMEMBRANE KINASE-mediated non-canonical signaling, which converges with TIR1/AFBs-mediated transcriptional regulation to coordinate plant growth and development. The identification of additional auxin signaling components and their regulation will continue to open new avenues of research in this field, leading to an increasingly deeper, more comprehensive understanding of how auxin signals are interpreted at the cellular level to regulate plant growth and development.

“…In apple, 31 putative ARF genes have been identified and divided into the following three subfamilies: I, II, and III [ 147 ]. Furthermore, the function of MdARF13 was investigated, and the MdARF13 protein was found to interact with the Aux/IAA repressor MdIAA121 through its C-terminal dimerization domain [ 148 ]. The degradation of MdIAAs mediated by TRANSPORT INHIBITOR RESISTANT 1 (MdTIR1) is essential for apple auxin signal transduction and root-growth regulation [ 149 ].…”

Section: Rootstock Genetic and Molecular Regulationmentioning

confidence: 99%

Root Breeding in the Post-Genomics Era: From Concept to Practice in Apple

Zhou

Shu³

et al. 2022

Plants

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The development of rootstocks with a high-quality dwarf-type root system is a popular research topic in the apple industry. However, the precise breeding of rootstocks is still challenging, mainly because the root system is buried deep underground, roots have a complex life cycle, and research on root architecture has progressed slowly. This paper describes ideas for the precise breeding and domestication of wild apple resources and the application of key genes. The primary goal of this research is to combine the existing rootstock resources with molecular breeding and summarize the methods of precision breeding. Here, we reviewed the existing rootstock germplasm, high-quality genome, and genetic resources available to explain how wild resources might be used in modern breeding. In particular, we proposed the ‘from genotype to phenotype’ theory and summarized the difficulties in future breeding processes. Lastly, the genetics governing root diversity and associated regulatory mechanisms were elaborated on to optimize the precise breeding of rootstocks.