Young-Wang Na

The Complete Chloroplast Genome of Capsicum annuum var. glabriusculum Using Illumina Sequencing

Chloroplast (cp) genome sequences provide a valuable source for DNA barcoding. Molecular phylogenetic studies have concentrated on DNA sequencing of conserved gene loci. However, this approach is time consuming and more difficult to implement when gene organization differs among species. Here we report the complete re-sequencing of the cp genome of Capsicum pepper (Capsicum annuum var. glabriusculum) using the Illumina platform. The total length of the cp genome is 156,817 bp with a 37.7% overall GC content. A pair of inverted repeats (IRs) of 50,284 bp were separated by a small single copy (SSC; 18,948 bp) and a large single copy (LSC; 87,446 bp). The number of cp genes in C. annuum var. glabriusculum is the same as that in other Capsicum species. Variations in the lengths of LSC; SSC and IR regions were the main contributors to the size variation in the cp genome of this species. A total of 125 simple sequence repeat (SSR) and 48 insertions or deletions variants were found by sequence alignment of Capsicum cp genome. These findings provide a foundation for further investigation of cp genome evolution in Capsicum and other higher plants.

Chlorophyll Fluorescence as a Diagnostic Tool for Abiotic Stress Tolerance in Wild and Cultivated Strawberry Species

Chlorophyll (Chl) fluorescence analysis was used to assess stress tolerance in wild and cultivated strawberry species. We found that the parameters, photochemical quenching (1-qP), non-photochemical quenching (qN), and maximum quantum yield (Fv/Fm), can serve as stress indicators because they are sensitive to early responses to stress. The most sensitive region used for measuring Chl fluorescence in strawberry leaves was the upper surfaces of leaflets located in the middle of new leaves. An analysis of the Chl fluorescence characteristics of strawberry species showed that octoploid species had greater stress tolerance than diploid species. The ‘Whiteberry’ maintained high levels of 1-qP and qN through the dissipation of excess excitation energy as heat during early stress treatment. These results suggest that ‘Whiteberry’ has a photoinhibition system that allows it to respond to stress in a more sensitive manner than other cultivars. Therefore, among the Chl fluorescence parameters examined, 1-qP and qN, can serve as good indicators for comparing stress tolerance, and they can be used to simultaneously screen many plants for stress tolerance in strawberry breeding programs.