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A set of fluorescent protein‐based markers expressed from constitutive and arbuscular mycorrhiza‐inducible promoters to label organelles, membranes and cytoskeletal elements in Medicago truncatula
Author(s) -
Ivanov Sergey,
Harrison Maria J.
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12706
Subject(s) - biology , medicago truncatula , microbiology and biotechnology , golgi apparatus , apoplast , endosome , endomembrane system , organelle , vacuole , endoplasmic reticulum , cytoskeleton , cytoplasm , symbiosis , biochemistry , cell wall , cell , genetics , bacteria , intracellular
Summary Medicago truncatula is widely used for analyses of arbuscular mycorrhizal ( AM ) symbiosis and nodulation. To complement the genetic and genomic resources that exist for this species, we generated fluorescent protein fusions that label the nucleus, endoplasmic reticulum, Golgi apparatus, trans ‐Golgi network, plasma membrane, apoplast, late endosome/multivesicular bodies ( MVB ), transitory late endosome/ tonoplast, tonoplast, plastids, mitochondria, peroxisomes, autophagosomes, plasmodesmata, actin, microtubules, periarbuscular membrane ( PAM ) and periarbuscular apoplastic space ( PAS ) and expressed them from the constitutive At UBQ 10 promoter and the AM symbiosis‐specific Mt BCP 1 promoter. All marker constructs showed the expected expression patterns and sub‐cellular locations in M. truncatula root cells. As a demonstration of their utility, we used several markers to investigate AM symbiosis where root cells undergo major cellular alterations to accommodate their fungal endosymbiont. We demonstrate that changes in the position and size of the nuclei occur prior to hyphal entry into the cortical cells and do not require DELLA signaling. Changes in the cytoskeleton, tonoplast and plastids also occur in the colonized cells and in contrast to previous studies, we show that stromulated plastids are abundant in cells with developing and mature arbuscules, while lens‐shaped plastids occur in cells with degenerating arbuscules. Arbuscule development and secretion of the PAM creates a periarbuscular apoplastic compartment which has been assumed to be continuous with apoplast of the cell. However, fluorescent markers secreted to the periarbuscular apoplast challenge this assumption. This marker resource will facilitate cell biology studies of AM symbiosis, as well as other aspects of legume biology.