Discovery of new alleles at important gene loci through allele mining could support the rice improvement program to sustain national food security. Evaluation of the existing Indonesian local rice landraces is an important point to detect the potential of functional alleles. One of the bacterial leaf blight (BLB) resistance alleles, Xa7 was detected in Indonesian rice landrace germplasm, Parekaligolara. To validate this potential allele, field evaluation on the segregating population, expression analysis using real time RT-PCR, and sequencing were carried out. Two selected Parekaligolara progenies lines ($F_4$ and $F_6$) from double crosses with other selected landraces were clearly more resistant to a dominant Indonesian BLB, Race IV. Specific primers of Xa7-LD40 successfully amplified the alleles of $F_4$ and $F_6$ lines approximately 300 bp in length. The amplicon sequenced using vector-targeted primers, resulting 264 bp which were flanked between 602 and 866 bp sites. The translated sequence which produced 60 amino acids (open reading frame) ORF, showed homology with the encoding gene associated with the defense system to biotic stress, BTB/POZ. As integrated researches for many potential biotic and abiotic stresses alleles on Indonesian landraces germplasm, this outcome expectedly supports rice landraces utilization for developing of elite cultivars which survive on global changed conditions and benefiting to national food security.