Modulation of abscisic acid signaling via endosomal TOL proteins.

The phytohormone abscisic acid (ABA) functions in the control of plant stress responses, particularly in drought stress. A significant mechanism in attenuating and terminating ABA signals involves regulated protein turnover, with certain ABA receptors, despite their main presence in the cytosol and nucleus, subjected to vacuolar degradation via the Endosomal Sorting Complex Required for Transport (ESCRT) machinery. Collectively our findings show that discrete TOM1-LIKE (TOL) proteins, which are functional ESCRT-0 complex substitutes in plants, affect the trafficking for degradation of core components of the ABA signaling and transport machinery. TOL2,3,5 and 6 modulate ABA signaling where they function additively in degradation of ubiquitinated ABA receptors and transporters. TOLs colocalize with their cargo in different endocytic compartments in the root epidermis and in guard cells of stomata, where they potentially function in ABA-controlled stomatal aperture. Although the tol2/3/5/6 quadruple mutant plant line is significantly more drought-tolerant and has a higher ABA sensitivity than control plant lines, it has no obvious growth or development phenotype under standard conditions, making the TOL genes ideal candidates for engineering to improved plant performance.

In vitro interactions between Blautia hydrogenotrophica, Desulfovibrio piger and Methanobrevibacter smithii under hydrogenotrophic conditions.

Methanogens, reductive acetogens and sulfate-reducing bacteria play an important role in disposing of hydrogen in gut ecosystems. However, how they interact with each other remains largely unknown. This in vitro study cocultured Blautia hydrogenotrophica (reductive acetogen), Desulfovibrio piger (sulfate reducer) and Methanobrevibacter smithii (methanogen). Results revealed that these three species coexisted and did not compete for hydrogen in the early phase of incubations. Sulfate reduction was not affected by B. hydrogenotrophica and M. smithii. D. piger inhibited the growth of B. hydrogenotrophica and M. smithii after 10 h incubations, and the inhibition on M. smithii was associated with increased sulfide concentration. Remarkably, M. smithii growth lag phase was shortened by coculturing with B. hydrogenotrophica and D. piger. Formate was rapidly used by M. smithii under high acetate concentration. Overall, these findings indicated that the interactions of the hydrogenotrophic microbes are condition-dependent, suggesting their interactions may vary in gut ecosystems.

The biological feasibility and social context of gene-edited, caffeine-free coffee.

Coffee, especially the species Coffea arabica and Coffea canephora, is one of the world's most consumed beverages. The consumer demand for caffeine-free coffee is currently being met through chemical decaffeination processes. However, this method leads to loss of beverage quality. In this review, the feasibility of using gene editing to produce caffeine-free coffee plants is reviewed. The genes XMT (7-methylxanthosine methyltransferase) and DXMT (3,7-dimethylxanthine methyltransferase) were identified as candidate target genes for knocking out caffeine production in coffee plants. The possible effect of the knock-out of the candidate genes was assessed. Using Agrobacterium tumefaciens-mediated introduction of the CRISPR-Cas system to Knock out XMT or DXMT would lead to blocking caffeine biosynthesis. The use of CRISPR-Cas to genetically edit consumer products is not yet widely accepted, which may lead to societal hurdles for introducing gene-edited caffeine-free coffee cultivars onto the market. However, increased acceptance of CRISPR-Cas/gene editing on products with a clear benefit for consumers offers better prospects for gene editing efforts for caffeine-free coffee.