bims-plasge 2023-04-30 papers

Issue of 2023–04–30
two papers selected by
Vera S. Bogdanova, ИЦиГ СО РАН

Plant Physiol. 2023 Apr 25. pii: kiad258. [Epub ahead of print]

DELAYED GREENING 409 encodes a dual-localized pentatricopeptide repeat protein required for chloroplast and mitochondrial development.

Huiying Wang, Jing Liu, Wei Zhao, William Terzaghi, Linbin Deng, Hongfang Liu, Qiwei Zheng, Shihang Fan, Wei Hua, Ming Zheng.

In ﬂowering plants, hundreds of RNA editing events occur in the chloroplasts and mitochondria during post-transcriptional processes. Although several pentatricopeptide repeat (PPR) proteins have been shown to form the editosome core, the precise interactions between the different editing factors are still obscure. Here, we isolated an Arabidopsis (Arabidopsis thaliana) PPR protein, designated DELAYED GREENING409 (DG409), that was dually targeted to chloroplasts and mitochondria. This protein consists of 409 amino acids with seven PPR motifs but lacks a C-terminal E, E + or DYW domain. A mild dg409 knockdown mutant displays a sickly phenotype. In this mutant, the young leaves are pale green and turn green at maturity, and the development of chloroplasts and mitochondria is severely disrupted. Complete loss of DG409 function results in defective embryos. Transcriptomic analysis of the dg409 knockdown plants showed some editing defects in genes from both organelles, including CASEINOLYTIC PROTEASE P (clpP)-559, RNA POLYMERASE SUBUNIT ALPHA (rpoA)-200, ACETYL-COA CARBOXYLASE CARBOXYL TRANSFERASE SUBUNIT BETA (accD)-1568, NADH DEHYDROGENASE SUBUNIT 7 (nad7)-1505 and RIBOSOMAL PROTEIN S3 (rps3)-1344. RNA immunoprecipitation (RIP) showed that DG409 was associated with the targeted transcripts in vivo. Interaction assays revealed that DG409 directly interacted with two DYW-type PPR proteins [EARLY CHLOROPLAST BIOGENESIS2 (AtECB2) and DYW DOMAIN PROTEIN2 (DYW2)] and three multiple organellar RNA editing factors (MORF2, MORF8 and MORF9). These results indicate that DG409 is involved in RNA editing via protein complexes and is therefore essential for chloroplast and mitochondrial development.

Keywords: Arabidopsis thaliana ; PPR; RNA editing; chloroplast and mitochondrial development; dual-localization

DOI: https://doi.org/10.1093/plphys/kiad258

Plants (Basel). 2023 Apr 17. pii: 1674. [Epub ahead of print]12(8):

Genetic Mapping of Flavonoid Grain Pigments in Durum Wheat.

Natalia Sgaramella, Domenica Nigro, Antonella Pasqualone, Massimo Antonio Signorile, Barbara Laddomada, Gabriella Sonnante, Emanuela Blanco, Rosanna Simeone, Antonio Blanco.

Pigmented cereal grains with high levels of flavonoid compounds have attracted the attention of nutritional science backing the development of functional foods with claimed health benefits. In this study, we report results on the genetic factors controlling grain pigmentation in durum wheat using a segregant population of recombinant inbred lines (RILs) derived from a cross between an Ethiopian purple grain accession and an Italian amber grain cultivar. The RIL population was genotyped by the wheat 25K SNP array and phenotyped for total anthocyanin content (TAC), grain color, and the L*, a*, and b* color index of wholemeal flour, based on four field trials. The mapping population showed a wide variation for the five traits in the different environments, a significant genotype x environment interaction, and high heritability. A total of 5942 SNP markers were used for constructing the genetic linkage map, with an SNP density ranging from 1.4 to 2.9 markers/cM. Two quantitative trait loci (QTL) were identified for TAC mapping on chromosome arms 2AL and 7BS in the same genomic regions of two detected QTL for purple grain. The interaction between the two QTL was indicative of an inheritance pattern of two loci having complementary effects. Moreover, two QTL for red grain color were detected on chromosome arms 3AL and 3BL. The projection of the four QTL genomic regions on the durum wheat Svevo reference genome disclosed the occurrence of the candidate genes Pp-A3, Pp-B1, R-A1, and R-B1 involved in flavonoid biosynthetic pathways and encoding of transcription factors bHLH (Myc-1) and MYB (Mpc1, Myb10), previously reported in common wheat. The present study provides a set of molecular markers associated with grain pigments useful for the selection of essential alleles for flavonoid synthesis in durum wheat breeding programs and enhancement of the health-promoting quality of derived foods.

Keywords: anthocyanins; candidate genes; grain color; nutritional quality; purple grains; regulatory genes; transcription factors; wheat

DOI: https://doi.org/10.3390/plants12081674