RoKSN, a floral repressor, forms protein complexes with RoFD and RoFT to regulate vegetative and reproductive development in rose

FT/TFL1 family members have been known to be involved in the development and flowering in plants. In rose, RoKSN, a TFL1 homologue, is a key regulator of flowering, whose absence causes continuous flowering. Our objectives are to functionally validate RoKSN and to explore its mode of action in rose.We complemented Arabidopsis tfl1 mutants and ectopically expressed RoKSN in a continuous-flowering (CF) rose. Using different protein interaction techniques, we studied RoKSN interactions with RoFD and RoFT and possible competition. In Arabidopsis, RoKSN complemented the tfl1 mutant by rescuing late flowering and indeterminate growth. In CF roses, the ectopic expression of RoKSN led to the absence of flowering. Different branching patterns were observed and some transgenic plants had an increased number of leaflets per leaf. In these transgenic roses, floral activator transcripts decreased. Furthermore, RoKSN was able to interact both with RoFD and the floral activator, RoFT. Protein interaction experiments revealed that RoKSN and RoFT could compete with RoFD for repression and activation of blooming, respectively. We conclude that RoKSN is a floral repressor and is also involved in the vegetative development of rose. RoKSN forms a complex with RoFD and could compete with RoFT for repression of flowering

Affricates and Obstruent Geminates in Thurgovian

My Master of Arts paper has demonstrated that Thurgovian obstruents show a threefold contrast, namely between short stops (singletons), long stops (geminates) and affricates. Thurgovian is a High Alemannic dialect spoken in the northeast of Switzerland, in the canton of Thurgau. Thurgovian belongs to the West Germanic languages and thus to the Indo-European family.Fritz Enderlin also mentions the threefold contrast in the dialect variety of Kesswil (Upper Thurgovian), but doesn t specifically refer to it. Beside his research and this Master of Arts paper, the threefold contrast in Thurgovian has never been investigated before. For the first time Thurgovian affricates were acoustically measured, this was done by this study, which is based on the dissertation of Astrid Kraehenmann.In Standard German the contrast between long stops and affricates does no longer exist. The main opposition within the obstruents in Standard German and English is the presence or absence of aspiration, and not distinctive consonant length as in Thurgovian.Recorded, measured and evaluated were short stops, long stops and affricates in all word positions. The Thurgovian stops are /p/, /t/ and /k/, the affricates are /pf/, /ts/ and /kx/. Already Kraehenmann has shown that short stops contrast with long stops in Thurgovian. Her result, that closure duration (CD) and not voice onset time (VOT) is the important measure to distinguish between geminates and singletons, was confirmed by this study. The CDs of geminates in medial position are even two times longer than the ones of singletons.This Master of Arts paper was the first not only to point out that a threefold contrast exists, but also to establish that the CD of affricates lies between the one of singletons and geminates. This means in medial word position, where the CD of a geminate or a long stop is about three times the one of a singleton, that the CD of affricates is about twice as long as the one of singletons. An affricate with a geminate CD followed by one fricative portion is a geminate affricate. Therefore can be presumed that Thurgovian has geminate affricates in medial word position. However, this presumption must be verified by measuring the duration of the fricative portion.The sequence singleton-affricate-geminate is also maintained in initial and final word position, even if the CD of initial and final geminates is only about twice as long as the one of singletons. This concludes that three distinctive consonant lengths exist in Thurgovian (for this result no distinction was made between surface and underlying representation).One part of this Master of Arts paper focuses on the socio-linguistic question of differences between generations, which was not investigated by Kraehenmann either. Three of the six native speakers belong to the younger and three to the older generation. The main results are the following: The older generation produces longer geminate and affricate CDs than the younger one, while the singleton CDs are quite the same for both generations.The measurements of the singletons, geminates and affricates are entirely listed in the printed copy

Differences in stability of seed-associated microbial assemblages in response to invasion by phytopathogenic microorganisms

Seeds are involved in the vertical transmission of microorganisms from one plant generation to another and consequently act as reservoirs for the plant microbiota. However, little is known about the structure of seed-associated microbial assemblages and the regulators of assemblage structure. In this work, we have assessed the response of seed-associated microbial assemblages of Raphanus sativus to invading phytopathogenic agents, the bacterial strain Xanthomonas campestris pv. campestris (Xcc) 8004 and the fungal strain Alternaria brassicicola Abra43. According to the indicators of bacterial (16S rRNA gene and gyrB sequences) and fungal (ITS1) diversity employed in this study, seed transmission of the bacterial strain Xcc 8004 did not change the overall composition of resident microbial assemblages. In contrast seed transmission of Abra43 strongly modified the richness and structure of fungal assemblages without affecting bacterial assemblages. The sensitivity of seed-associated fungal assemblage to Abra43 is mostly related to changes in relative abundance of closely related fungal species that belong to the Alternaria genus. Variation in stability of the seed microbiota in response to Xcc and Abra43 invasions could be explained by differences in seed transmission pathways employed by these micro-organisms, which ultimately results in divergence in spatio-temporal colonization of the seed habitat