We have assembled a proteome map for Arabidopsis thaliana from high-density, organ-specific proteome catalogs that we generated for different organs, developmental stages, and undifferentiated cultured cells. We matched 86,456 unique peptides to 13,029 proteins and provide expression evidence for 57 gene models that are not represented in the TAIR7 protein database. Analysis of the proteome identified organ-specific biomarkers and allowed us to compile an organ-specific set of proteotypic peptides for 4105 proteins to facilitate targeted quantitative proteomics surveys. Quantitative information for the identified proteins was used to establish correlations between transcript and protein accumulation in different plant organs. The Arabidopsis proteome map provides information about genome activity and proteome assembly and is available as a resource for plant systems biology.

The precise delivery of male to female gametes during reproduction in eukaryotes requires complex signal exchanges and a flawless communication between male and female tissues. In angiosperms, molecular mechanisms have recently been revealed that are crucial for the dialog between male (pollen tube) and female gametophytes required for successful sperm delivery. When pollen tubes reach the female gametophyte, they arrest growth, burst and discharge their sperm cells. These processes are under the control of the female gametophyte via the receptor-like serine-threonine kinase (RLK) FERONIA(FER). However, the male signaling components that control the sperm delivery remain elusive. Here, we show that ANXUR1 and ANXUR2(ANX1, ANX2), which encode the closest homologs of the FER-RLK in Arabidopsis, are preferentially expressed in pollen. Moreover,ANX1-YFP and ANX2-YFP fusion proteins display polar localization to the plasma membrane at the tip of the pollen tube. Finally, genetic analyses demonstrate that ANX1 and ANX2 function redundantly to control the timing of pollen tube discharge as anx1 anx2 double-mutant pollen tubes cease their growth and burst in vitro and fail to reach the female gametophytes in vivo. We propose that ANX-RLKs constitutively inhibit pollen tube rupture and sperm discharge at the tip of growing pollen tubes to sustain their growth within maternal tissues until they reach the female gametophytes. Upon arrival, the female FER-dependent signaling cascade is activated to mediate pollen tube reception and fertilization, while male ANX-dependent signaling is deactivated, enabling the pollen tube to rupture and deliver its sperm cells to effect fertilization.

To investigate which aspects of contemporary human Y-chromosome variation in Europe are characteristic of primary colonization, late-glacial expansions from refuge areas, Neolithic dispersals, or more recent events of gene flow, we have analyzed, in detail, haplogroup I (Hg I), the only major clade of the Y phylogeny that is widespread over Europe but virtually absent elsewhere. The analysis of 1,104 Hg I Y chromosomes, which were identified in the survey of 7,574 males from 60 population samples, revealed several subclades with distinct geographic distributions. Subclade I1a accounts for most of Hg I in Scandinavia, with a rapidly decreasing frequency toward both the East European Plain and the Atlantic fringe, but microsatellite diversity reveals that France could be the source region of the early spread of both I1a and the less common I1c. Also, I1b*, which extends from the eastern Adriatic to eastern Europe and declines noticeably toward the southern Balkans and abruptly toward the periphery of northern Italy, probably diffused after the Last Glacial Maximum from a homeland in eastern Europe or the Balkans. In contrast, I1b2 most likely arose in southern France/Iberia. Similarly to the other subclades, it underwent a postglacial expansion and marked the human colonization of Sardinia approximately 9,000 years ago.