Biology subjects

Drea, S.

Publications and source records attributed to Drea, S..

3 recordsLinked to original sources

bioRxiv2019

LYS3 encodes a prolamin-box-binding transcription factor that controls embryo growth in barley and wheat

Mutations at the LYS3 locus in barley have multiple effects on grain development, including an increase in embryo size and a decrease in endosperm starch content. The gene underlying LYS3 was identified by genetic mapping and mutations in this gene were identified in all four barley lys3 alleles. LYS3 encodes a transcription factor called Prolamin Binding Factor (PBF). Its role in controlling embryo size was confirmed using wheat TILLING mutants. To understand how PBF controls embryo development, we studied its spatial and temporal patterns of expression in developing grains. The PBF gene is expressed in both the endosperm and the embryos, but the timing of expression in these organs differs. PBF expression in wild-type embryos precedes the onset of embryo enlargement in lys3 mutants, suggesting that PBF suppresses embryo growth. We predicted the down-stream target genes of PBF in wheat and found them to be involved in a wide range of biological processes, including organ development and starch metabolism. Our work suggests that PBF may influence embryo size and endosperm starch synthesis via separate gene control networks. HIGHLIGHTSO_LILYS3 encodes a transcription factor called Prolamin Binding Factor (PBF) that is expressed in grains only. C_LIO_LIWheat and barley LYS3/PBF mutants have enlarged embryos suggesting that this gene suppresses embryo growth. C_LIO_LIThe down-stream target genes of PBF in wheat are predicted to be involved in a wide range of biological processes including organ development and starch metabolism. C_LI

plant biology↗

bioRxiv2019

Programmed Cell Death in Developing Brachypodium distachyon Grain

O_LIThe normal developmental sequence in a grass grain entails the death of several maternal and filial tissues in a genetically regulated process termed programmed cell death (PCD). The progression and molecular aspects of PCD in developing grain have been reported for domesticated species like barley, rice, maize and wheat. Here, we report a detailed investigation of PCD in the developing grain of a wild model species, Brachypodium distachyon.\nC_LIO_LIWe detected PCD in developing Brachypodium grains using molecular and histological approaches. We also identified and surveyed the expression of Brachypodium orthologs of protease genes known to contribute to grain PCD.\nC_LIO_LIWe found that Brachypodium nucellus degenerates by PCD in a centrifugal pattern following anthesis, although at a slower rate compared to cultivated cereals. Mesocarp PCD was not coordinated with endosperm development. Brachypodium lacks an expansion of vacuolar processing enzymes known for their roles in nucellar PCD.\nC_LIO_LICombined with existing knowledge on grain PCD, our study suggests the importance of rapid nucellar PCD for grain size and that the pattern of mesocarp PCD affects grain shape.\nC_LI

plant biology↗

bioRxiv2019

Delineation of post-phloem assimilate transport pathway into developing caryopsis of Brachypodium distachyon

Assimilates stored in mature cereal grains are mobilized from source tissues and transported towards developing grains through the vascular bundle. Due to the lack of direct vascular connection between maternal grain vascular bundle and filial tissues, post-phloem transportation of assimilates into grain endosperm relies on transfer cells that lie between the grain vascular bundle and the endosperm. Here, we propose Caryopsis Endosperm Assimilate Acquisition Route (CEAAR) models that describes the exact path of assimilate import into caryopsis endosperms. Using fluorescent tracer dyes we also delineated the route of assimilate delivery into Brachypodium distachyon endosperm and classified it as ventral circuitous (vc-CEAAR), an assimilate import model also found in rice. Furthermore, we report a detailed anatomical study of post-phloem assimilate transport pathway in developing grains of Brachypodium distachyon. Our results highlight major anatomical similarities and differences between the grain post-phloem transfer cells of Brachypodium and those of crop species such as rice, wheat, and barley relevant to post-phloem assimilate transport.\n\nHighlightsO_LIBased on existing work, we propose Caryopsis Endosperm Assimilate Acquisition Route (CEAAR) models, that describes the exact path of assimilate import into caryopsis endosperms.\nC_LIO_LIThe structure of the post-phloem transfer cells of Brachypodium distachyon mirrors temperate and tropical cereals.\nC_LIO_LIAssimilate delivery into Brachypodium distachyon endosperm is identical to assimilate import into rice endosperm.\nC_LI

cell biology↗