Microsatellite-based evidences of genetic bottlenecks in the cryptic species “Andrographis paniculata Nees”: a potential anticancer agent

Abstract

Andrographis paniculata (AP) is a medicinal plant species introduced into Malaysia. To address the genetic structure and evolutionary connectedness of the Malaysian AP with the Indian AP, a DNA sequence analysis was conducted based on 24 microsatellite markers. Out of the 24 primer sets, seven novel microsatellite primers were designed and amplified intra-specifically according to the available Indian AP sequences at the National Centre for Biotechnology Information (NCBI), where 17 of them were amplified using the cross-species strategy by employing the primers belonging to Acanthus ilicifolius Linn (Acanthaceae) and Lumnitzera racemosa Wild (Combretaceae). The primers were then applied on the Malaysian AP accessions. Sixteen of the new microsatellite loci were amplified successfully. Analysis of these microsatellite sequences, revealed some significant differences between the Indian and Malaysian AP accessions in terms of the size and type of the repeat motifs. These findings depicted the cryptic feature of this species. Despite identifying several heterozygous alleles no polymorphism was observed in the detected loci of the selected accessions. This situation was in concordance with the presence of "fixed heterozygosity" phenomenon in the mentioned loci. Accordingly, this was fully consistent with the occurrence of the genetic bottleneck and founder effect within Malaysian AP population. Apart from the amplification of new microsatellites in this species, our observations could be in agreement with the risk of genetic depletion and consequently extinction of this precious herb in Malaysia. This issue should be taken into consideration in the future studies.

A Classical Genetic Solution to Enhance the Biosynthesis of Anticancer Phytochemicals in Andrographis paniculata Nees

“…This exactly fits the situation that Malaysian AP has been encountered with. On the one hand, a high level of homozygosity along with a special type of monomorphic heterozygosity (fixed heterozygosity) was revealed using microsatellite markers [54]. Further, randomly amplified polymorphic DNA (RAPD) markers indicated a low genetic diversity among the Malaysian AP populations [27].…”

“…The presence of a subtle level of this phenomenon in AP has been noticed recently [27], and we assume that a part of the detected heterosis could be generated because of suppressing the genetic depression in the F 1 hybrids. However, this behavior could have specifically been intensified in the bottlenecked population of AP in Malaysia [54]. In light of the convincing molecular evidences on the Malaysian AP populations [27], [54], the use of an F 2 population was dispensable to detect outbreeding depression.…”

“…However, this behavior could have specifically been intensified in the bottlenecked population of AP in Malaysia [54]. In light of the convincing molecular evidences on the Malaysian AP populations [27], [54], the use of an F 2 population was dispensable to detect outbreeding depression. Evidently, F 2 plants are employed when outbreeding depression might not be perceived in the F 1 generation due to high heterosis, and might only appear in the next generations.…”

“…This ensues when genetic variation underlying a quantitative characteristics controlled by genes that “act additively” within and between loci [70]. Hence, an evolutionary perspective could be drawn that these anticancer factors were originally controlled by additive gene action in the Indian ancestors of AP, however, their additive variance decreased because of a bottleneck event after their introduction to Malaysia [54]. The latter assumption gives raise the need for future studies to investigate the role of additive gene action in controlling the heritability of the andrographolides using different AP populations.…”

Salt stress-induced protein pattern associated with photosynthetic parameters and andrographolide content in Andrographis paniculata Nees

“…39) The obtained results have a high potential to be combined with different biochemical, 39) molecular 40,41) , and morphological 40,42) , data and can be used for resolving some critical issues in the herb such as crossability. 40,42,43) Electrophoretic information on the leaf proteins can be specifically matched with the seed protein data 39) of A. paniculata to make fruitful decisions on the breeding programs.…”