Arabidopsis ANGULATA10 is required for thylakoid biogenesis and mesophyll development

Abstract

SummaryThis study characterized ANU10, a novel chloroplast protein encoded by a nuclear gene in Arabidopsis, which influences leaf and chloroplast shape and is required for thylakoid stacking and grana formation.

Rapid identification of angulata leaf mutations using next-generation sequencing

“…Scale bars 2 mm that this might also be the case for other ANU genes that remain to be cloned. Indeed, this idea is validated by the recent cloning of ANU10, which was cloned using a conventional map-based approach and encodes a chloroplastlocalized protein that is required for normal grana stacking and leaf organogenesis (Casanova-Sáez et al 2014b). The anu1-1, anu4-1, anu9-1 and anu12-1 mutants described in this work turned out to be new alleles of the previously characterized SECA2, TOC33, NAP14 and CLPR1 genes (Jarvis et al 1998;Koussevitzky et al 2007;Shimoni-Shor et al 2010;Skalitzky et al 2011), all of which encode chloroplast-localized proteins.…”

Members of the DEAL subfamily of the DUF1218 gene family are required for bilateral symmetry but not for dorsoventrality in Arabidopsis leaves

“…Roots, shoots, and leaves longer than 5 mm were removed to obtain plant material enriched in leaf primordia and immediately frozen in liquid nitrogen. RNA purification and reverse transcription with random hexamers were carried out as described previously (Casanova-S aez et al, 2014). Three different biological replicates were used in triplicate reactions.…”

The ANGULATA7 gene encodes a DnaJ‐like zinc finger‐domain protein involved in chloroplast function and leaf development in Arabidopsis

“…In line with this idea, the systematic cloning of genes identified in our large‐scale screen for ethyl methanesulfonate (EMS)‐induced mutants with abnormal leaf size and/or shape has evidenced that not few of such genes code for enzymes that catalyze steps in the biosynthesis pathways of arginine (Mollá‐Morales et al ., ), cellulose (Rubio‐Díaz et al ., ) or tetrapyrroles (Quesada et al ., ). The two most abundant phenotypic classes identified in this screen comprise mutants carrying alleles of nuclear genes that encode subunits of the cytosolic ribosome (Van Minnebruggen et al ., ; Horiguchi et al ., ; Casanova‐Sáez et al ., ) and chloroplast‐localized proteins, respectively (Casanova‐Sáez et al ., ; Mateo‐Bonmatí et al ., , ). Remarkably, many of the mutations in genes that appear to be housekeeping do not cause a mere growth retardation, but instead they cause specific phenotypes, as other authors have previously reported (Tsukaya et al ., ).…”

“…Mutations in all these genes cause a pleiotropic phenotype that includes both defects in leaf size and shape and pale green pigmentation. The genes cloned so far include ANU1 , ANU4 , ANU9 , ANU10 and ANU12 (Casanova‐Sáez et al ., ; Mateo‐Bonmatí et al ., ), which in most cases encode proteins that contain an N‐terminal chloroplast transit peptide. We found our anu1 , anu4 , anu9 and anu12 mutants to be loss‐of‐function, viable alleles of the SECA2 , TRANSLOCON AT THE OUTER MEMBRANE OF CHLOROPLASTS 33 ( TOC33 ), NON‐INTRINSIC ABC PROTEIN 14 ( NAP14 ) and CLP PROTEASE PROTEOLYTIC SUBUNIT 1 ( CLPR1 ) genes (Jarvis et al ., ; Koussevitzky et al ., ; Shimoni‐Shor et al ., ; Skalitzky et al ., ).…”

“…We found our anu1 , anu4 , anu9 and anu12 mutants to be loss‐of‐function, viable alleles of the SECA2 , TRANSLOCON AT THE OUTER MEMBRANE OF CHLOROPLASTS 33 ( TOC33 ), NON‐INTRINSIC ABC PROTEIN 14 ( NAP14 ) and CLP PROTEASE PROTEOLYTIC SUBUNIT 1 ( CLPR1 ) genes (Jarvis et al ., ; Koussevitzky et al ., ; Shimoni‐Shor et al ., ; Skalitzky et al ., ). The ANU10 gene, by contrast, was found to encode a conserved, previously undescribed protein that is widespread throughout the plant kingdom and is required for thylakoid stacking in chloroplasts (Casanova‐Sáez et al ., ), demonstrating that mutational approaches remain a powerful tool to identify new molecular components even for processes that have been intensively surveyed over the last decades, such as photosynthetic function.…”