Asteraceae is one of the invasive plant family. Invasive plants have more ability in tolerating high temperatures with the role of the Hsp70 mechanism. The Hsp70 gene is conserved in cells as a form of adaptation to some environmental stresses, one of which is temperature stress. The difference of average temperature between Universitas Indonesia-Depok (28.6 °C) and Cibodas Botanical Garden (20.06 °C) become the basis of this research to see the level of Hsp70 gene expression in Ageratum conyzoides and Synedrella nodiflora. RNA isolation from the leaf tissues was carried out using modified CTAB method followed by cDNA synthesis. The cDNA obtained is then amplified by PCR using a Hsp70 primer from Arabidopsis thaliana. The results of this research using in silico techniques showed a partial amplification of the Hsp70 gene and the presence of nucleotide variations in Universitas Indonesia-Depok and Cibodas Botanical Garden at the positions number 110 (Ageratum conyzoides) and 108 (Synedrella nodiflora). These variations resulted in different amino acids but did not change the protein structure prediction of the samples.

Synedrella nodiflora is an invasive species originated from tropical America and now has spread throughout Indonesia. We analysed the ability of Synedrella nodiflora from the level of HSP70 gene expression at different heat stress in urban tropical lowland landscape Universitas Indonesia.  We used the qPCR to quantify the level of HSP70 gene expression and analysed using Pfaffl model. We found the level of HSP70 gene expression got higher related to elevated temperature from 29oC to 39oC with a range of fold from 123.1 to 1676.9. This ability reflects the adaptive plasticity of Synedrella nodiflora in the course of the invasion process.