ORCID Profile
0000-0002-7522-7942
Current Organisation
Julius Kühn-Institut
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Publisher: Oxford University Press (OUP)
Date: 10-12-2015
DOI: 10.1104/PP.15.00786
Publisher: Wiley
Date: 03-2022
DOI: 10.1111/PPL.13653
Abstract: Overexpression of the vacuolar sugar transporter TST1 in Arabidopsis leads to higher seed lipid levels and higher total seed yield per plant. However, effects on fruit biomass have not been observed in crop plants like melon, strawberry, cotton, apple, or tomato with increased tonoplast sugar transporter (TST) activity. Thus, it was unclear whether overexpression of TST in selected crops might lead to increased fruit yield, as observed in Arabidopsis. Here, we report that constitutive overexpression of TST1 from sugar beet in the important crop species Camelina sativa (false flax) resembles the seed characteristics observed for Arabidopsis upon increased TST activity. These effects go along with a stimulation of sugar export from source leaves and not only provoke optimised seed properties like higher lipid levels and increased overall seed yield per plant, but also modify the root architecture of BvTST1 overexpressing Camelina lines. Such mutants grew longer primary roots and showed an increased number of lateral roots, especially when developed under conditions of limited water supply. These changes in root properties result in a stabilisation of total seed yield under drought conditions. In summary, we demonstrate that increased vacuolar TST activity may lead to optimised yield of an oil‐seed crop species with high levels of healthy ω3 fatty acids in storage lipids. Moreover, since BvTST1 overexpressing Camelina mutants, in addition, exhibit optimised yield under limited water availability, we might devise a strategy to create crops with improved tolerance against drought, representing one of the most challenging environmental cues today and in future.
Publisher: Cold Spring Harbor Laboratory
Date: 22-09-2021
DOI: 10.1101/2021.09.21.461191
Abstract: As the major sugar-producing crop in the northern hemisphere, sugar beet taproots store sucrose at a concentration of about 20 %. While the vacuolar sucrose loader TST has already been identified in the taproot, sugar transporters mediating sucrose uptake across the plasma membrane of taproot parenchyma cells remained unknown. We electrophysiologically examined taproots for proton-coupled sugar uptake and identified potentially involved transporters by transcriptomic profiling. After cloning, the transporter features were studied in the heterologous Xenopus laevis oocyte expression system using the two-electrode voltage cl technique. Insights into the structure were gained by 3D homology modeling. As with glucose, sucrose stimulation of taproot parenchyma cells caused inward H + -fluxes and plasma membrane depolarization, indicating a sugar roton symport mechanism. As one potential candidate for sugar uploading, the BvPMT5a was characterized as a H + -driven low-affinity glucose transporter, which does not transport sucrose. BvSTP13 operated as a high-affinity H + /sugar symporter, transporting glucose and to some extent sucrose due to a binding cleft plasticity. Both transporter genes were upregulated upon cold exposure, with the transport capacity of BvSTP13 being more cold-resistant than BvPMT5a. Identification of BvPMT5a and BvSTP13 as taproot sugar transporters could improve breeding of cold-tolerant sugar beet to provide a sustainable energy crop.
Publisher: Wiley
Date: 09-2022
DOI: 10.1111/PPL.13776
Abstract: Boron (B) deficiency is a highly prominent nutrient disorder. While B‐efficient accessions have recently been identified in the highly B‐demanding crop oilseed rape, it remained unclear which physiological processes underlie B efficiency and which signaling pathways trigger an efficient B‐deficiency response. Here, we compared, under three different B supply conditions, two Brassica napus accessions with contrasting B efficiency. Shoot biomass formation, B distribution patterns and metabolic dynamics of different phytohormone species were studied using a combination of mass spectrometry‐based analyses and physiological measurements. Our results show that the B‐efficient accession CR2267 does not differ from the B‐inefficient accession CR2262 in terms of B accumulation and subcellular B‐partitioning, although it displays no morphological B‐deficiency symptoms under severe B‐deficient conditions. Investigating phytohormone metabolism revealed a strong accumulation of cytokinins in CR2267 at a developmental stage when striking B‐dependent differences in biomass and organ formation emerge in the two B. napus accessions. In contrast, elevated levels of the stress hormone abscisic acid as well as bioactive auxins, representing functional antagonists of cytokinins in shoots, were detected only in CR2262 . Our results indicate that superior B efficiency in CR2267 relies on a higher B utilization efficiency that builds on an earlier and higher cytokinin biosynthesis required for the maintenance of the shoot meristem activity and proper leaf development. We further conclude that an elevated abundance of cytokinins is not a consequence of better plant growth but rather a presumption for better plant growth under low‐B conditions.
Location: Germany
No related grants have been discovered for Benjamin Pommerrenig.