A Combined Proteome and Transcriptome Analysis of Developing Medicago truncatula Seeds

Abstract

A comparative study of proteome and transcriptome changes during Medicago truncatula (cultivar Jemalong) seed development has been carried out. Transcript and protein profiles were parallel across the time course for 50% of the comparisons made, but divergent patterns were also observed, indicative of post-transcriptional events. These data, combined with the analysis of transcript and protein distribution in the isolated seed coat, endosperm, and embryo, demonstrated the major contribution made to the embryo by the surrounding tissues. First, a remarkable compartmentalization of enzymes involved in methionine biosynthesis between the seed tissues was revealed that may regulate the availability of sulfur-containing amino acids for embryo protein synthesis during seed filling. This intertissue compartmentalization, which was also apparent for enzymes of sulfur assimilation, is relevant to strategies for modifying the nutritional value of legume seeds. Second, decreasing levels during seed filling of seed coat and endosperm metabolic enzymes, including essential steps in Met metabolism, are indicative of a metabolic shift from a highly active to a quiescent state as the embryo assimilates nutrients. Third, a concomitant persistence of several proteases in seed coat and endosperm highlighted the importance of proteolysis in these tissues as a supplementary source of amino acids for protein synthesis in the embryo. Finally, the data revealed the sites of expression within the seed of a large number of transporters implied in nutrient import and intraseed translocations. Several of these, including a sulfate transporter, were preferentially expressed in seeds compared with other plant organs. These findings provide new directions for genetic

The Proteome of Seed Development in the Model Legume Lotus japonicus

“…So far, 746 unique gene accession numbers identified from green and mature seeds constitute the Lotus resource. Similar 2-D gel or Sec-MudPIT-based proteomic studies of seed filling in Medicago and soybean identified 226 and 647 unique proteins, respectively (Gallardo et al, 2003(Gallardo et al, , 2007Hajduch et al, 2005;Agrawal et al, 2008). Comparing these Medicago and soybean proteins against the identified Lotus seed proteins (BLASTP e # 1 3 10 26 ), 39% of the proteins from Lotus were also identified in Medicago, and with soybean the overlap was 60%.…”

“…Met synthase and several other enzymes involved in amino acids metabolism have been identified in Medicago seed development (Gallardo et al, 2003(Gallardo et al, , 2007.…”

“…Refining the bioinformatics-based comparison presented above, we compiled starch enzyme identifications from the five seed proteomic studies ( Fig. 7; Gallardo et al, 2003Gallardo et al, , 2007Hajduch et al, 2005;Agrawal et al, 2008). Although legume seed starch metabolism may be different from the well-studied processes in leaves and in cereal grains, this approach provided good coverage of known starch biosynthetic and degradation pathways (Fig.…”

iTRAQ Protein Profile Analysis of Arabidopsis Roots Reveals New Aspects Critical for Iron Homeostasis

“…Posttranscriptional regulatory processes such as alternative splicing, RNA processing, and other processes may affect the efficiency of translation. A generally low congruency of proteomic and transcriptional profiles has been reported previously (Gallardo et al, 2007).…”

Two-dimensional gel electrophoretic protein profile analysis during seed development of Ocotea catharinensis: a recalcitrant seed species

“…Over latter years, several studies have focused on characterizing protein dynamics during plant development, as well as the associated genomes and transcriptomes involved (Roberts 2002;Heazlewood and Millar 2003;Chen and Harmon 2006;Gallardo et al 2007;Dam et al 2009). It has been demonstrated that proteomic analysis can generate relevant information towards elucidating the identity of those molecular mechanisms involved in developmental processes.…”