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Summary
Wild relatives of crops thrive in habitats where environmental conditions can be restrictive for productivity and survival of cultivated species. The genetic basis of this variability, particularly for tolerance to high temperatures, is not well understood. We examined the capacity of wild and cultivated accessions to acclimate to rapid temperature elevations that cause heat stress (HS).
We investigated genotypic variation in thermotolerance of seedlings of wild and cultivated accessions. The contribution of polymorphisms associated with thermotolerance variation was examined regarding alterations in function of the identified gene.
We show that tomato germplasm underwent a progressive loss of acclimation to strong temperature elevations. Sensitivity is associated with intronic polymorphisms in the HS transcription factor HsfA2 which affect the splicing efficiency of its pre‐mRNA. Intron splicing in wild species results in increased synthesis of isoform HsfA2‐II, implicated in the early stress response, at the expense of HsfA2‐I which is involved in establishing short‐term acclimation and thermotolerance.
We propose that the selection for modern HsfA2 haplotypes reduced the ability of cultivated tomatoes to rapidly acclimate to temperature elevations, but enhanced their short‐term acclimation capacity. Hence, we provide evidence that alternative splicing has a central role in the definition of plant fitness plasticity to stressful conditions.
The African shieldbug genus Afrius Stål, 1870 is revised. Cantheconidea migratoria Distant, 1913 and A. williamsi Miller, 1952 are proposed as junior synonyms of A. (Subafrius) flavirostrum (Signoret, 1861) whereas Canthecona marmorata Dallas, 1851, Canthecona annulipes Dallas, 1851 and A. rubromarginatus Bergroth, 1903 are proposed as junior synonyms of A. (Afrius) purpureus (Westwood, 1837) based on the general morphology and genitalia of the species. The three valid species, viz. A. (Subafrius) flavirostrum, A. (Afrius) kolleri Schouteden, 1911 and A. (Afrius) purpureus, are redescribed with details of male and female genitalia morphology, and a lectotype is designated for A. (Afrius) kolleri. A key to identify the species as well as an update of the geographical distribution for each species are provided, including new records for A. (Afrius) purpureus.
We have encountered two polymorphs of the title compound, C24H16B2OS2, both of which display almost the same unit-cell parameters. Compound (I) crystallizes in the non-centrosymmetric space group P21 with four molecules in the asymmetric unit. These molecules are related by pseudosymmetry. As a result, the space group looks like P21/c, but the structure cannot be refined successfully in that space group. Compound (II) on the other hand crystallizes in the centrosymmetric space group P21/c with only two molecules in the asymmetric unit. The crystals studied for (I) and (II) were both non-merohedral twins.