Unravelling the proteomic profile of rice meiocytes during early meiosis

Abstract

Transfer of genetic traits from wild or related species into cultivated rice is nowadays an important aim in rice breeding. Breeders use genetic crosses to introduce desirable genes from exotic germplasms into cultivated rice varieties. However, in many hybrids there is only a low level of pairing (if existing) and recombination at early meiosis between cultivated rice and wild relative chromosomes. With the objective of getting deeper into the knowledge of the proteins involved in early meiosis, when chromosomes associate correctly in pairs and recombine, the proteome of isolated rice meiocytes has been characterized by nLC-MS/MS at every stage of early meiosis (prophase I). Up to 1316 different proteins have been identified in rice isolated meiocytes in early meiosis, being 422 exclusively identified in early prophase I (leptotene, zygotene, or pachytene). The classification of proteins in functional groups showed that 167 were related to chromatin structure and remodeling, nucleic acid binding, cell-cycle regulation, and cytoskeleton. Moreover, the putative roles of 16 proteins which have not been previously associated to meiosis or were not identified in rice before, are also discussed namely: seven proteins involved in chromosome structure and remodeling, five regulatory proteins [such as SKP1 (OSK), a putative CDK2 like effector], a protein with RNA recognition motifs, a neddylation-related protein, and two microtubule-related proteins. Revealing the proteins involved in early meiotic processes could provide a valuable tool kit to manipulate chromosome associations during meiosis in rice breeding programs. The data have been deposited to the ProteomeXchange with the PXD001058 identifier.

Proteomic and phosphoproteomic analyses reveal extensive phosphorylation of regulatory proteins in developing rice anthers

“…Recently, a proteomic analysis for early rice male meiocytes was published, in which 1316 expressed proteins were identified (Collado‐Romero et al ., ). Comparative analysis with our phosphoproteomic data revealed that 414 meiocytes expressed proteins were phosphorylated (Figure a and Table S6).…”

“…Further analysis found that, except the meiosis-related proteins listed in the Table 1, additional 15 phosphorylated proteins were annotated as chromatin-associated ones (Table S4). Interestingly, five phosphorylated proteins, LOC_Os02g01740 (a putative helicase), LOC_Os03g06220 (a DEAD-box ATP-dependent RNA helicase), LOC_Os02g36710 (a SET-domaincontaining protein), LOC_Os03g52310 (a transposon protein) and LOC_Os04g18090 (Histone H1), were exclusively identified in early prophase I stage during meiosis (Collado-Romero et al, 2014). Secondly, 117 phosphorylated proteins were classified into protein synthesis group, including ribosomal protein, initiation and elongation factor sub-groups, in which 52 were identified in rice early meiosis (Table S2 and S6).…”

Identification and validation of reference genes for RT-qPCR normalization in wheat meiosis

“…In fact, for some wheat genotypes as those carrying the Ph1 deletion, meiosis is not synchronized 43 , making the identification of each meiosis stage even more complicated. In addition, and as far as we know, although there are some massive approaches to study meiosis using transcriptomics and proteomics in cereals like maize [44][45][46] , rice 47,48 and other plants 49 , the only massive transcriptomic study covering the whole meiosis process in wheat anthers was performed by Crismani and colleagues 23 , using the Affymetrix GeneChip Wheat Genome Array. Recent studies have examined gene expression in wheat meiotic anthers using RNA-seq 31,38 .…”

Proteomic analysis of lysine acetylation provides strong evidence for involvement of acetylated proteins in plant meiosis and tapetum function

“…To detect potential KAC proteins involved in rice meiosis, we next conducted a comparison analysis between the rice meiocyte proteome reported previously (Collado-Romero et al, 2014) and the RAM lysine acetylome here. We found that 357 acetylated proteins, representing over half of the total identified in the RAM, were present in rice meiocytes (Figure 5a and Table S6).…”