SUMMARYNucleocytoplasmic partitioning of core clock components is essential for the proper operation of the circadian system. Previous work has shown that the F-box protein ZEITLUPE (ZTL) and clock element GIGANTEA (GI) heterodimerize in the cytosol, thereby stabilizing ZTL. Here, we report that ZTL post-translationally and reciprocally regulates protein levels and nucleocytoplasmic distribution of GI in Arabidopsis. We use ectopic expression of the N-terminus of ZTL, which contains the novel, light-absorbing region of ZTL (the LOV domain), transient expression assays and ztl mutants to establish that the levels of ZTL, a cytosolic protein, help govern the abundance and distribution of GI in the cytosol and nucleus. Ectopic expression of the ZTL N-terminus lengthens period, delays flowering time and alters hypocotyl length. We demonstrate that these phenotypes can be explained by the competitive interference of the LOV domain with endogenous GI-ZTL interactions. A complex of the ZTL N-terminus polypeptide with endogenous GI (LOV-GI) blocks normal GI function, causing degradation of endogenous ZTL and inhibition of other GI-related phenotypes. Increased cytosolic retention of GI by the LOV-GI complex additionally inhibits nuclear roles of GI, thereby lengthening flowering time. Hence, we conclude that under endogenous conditions, GI stabilization and cytoplasmic retention occurs naturally through a LOV domainmediated GI-ZTL interaction, and that ZTL indirectly regulates GI nuclear pools by sequestering GI to the cytosol. As the absence of either GI or ZTL compromises clock function and diminishes the protein abundance of the other, our results highlight how their reciprocal co-stabilization is essential for robust circadian oscillations.
We conducted a two‐treatment randomized control trial in northern Ghana to investigate how bundling index insurance with agricultural loans affects smallholder access to credit. In one treatment, farmer groups were invited to apply for production loans bundled with an index insurance contract that, in the event of a drought, indemnifies farmers directly (micro‐insured loans). In the second treatment, farmer groups were invited to apply for production loans bundled with an index insurance contract that, in the event of a drought, indemnifies the lender on the condition that the indemnity be used to retire the farmer's debt obligation (meso‐insured loans). Farmer groups in the control category were invited to apply for uninsured loans. We find that insured loans increase farmers' likelihood of receiving credit by between 15 and 21 percentage points. Exploring the mechanisms of this effect, we find no impact on the likelihood that farmers apply for credit but do find an increase in the likelihood of loan approvals of between 17 and 25 percentage points.
Index insurance has been heralded as a potential solution to risk management problems faced by smallholder farmers in developing countries. Despite its potential, demand for standalone index insurance contracts has remained low in early field trials. We investigate the willingness to pay for drought index insurancebacked loans in northern Ghana using contingent valuation. We find that index insurance lowers overall demand for agricultural loans. We also compare microlevel index insurance, provided directly to farmers, with meso-level insurance, provided to the credit agency and find that farmers appear to prefer micro-level insurance. Finally, farmers are willing to pay to avoid basis risk.
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