The aim of this study was to develop PCR primer sets for the rapid classification of lactic acid bacteria (LAB). Published gene sequences for LAB carbohydrate metabolic enzymes were collected from the NCBI GenBank, and 45 primer sets were designed using the gene sequences. Twelve species of LAB were used as reference strains: Lactobacillus brevis, Lactobacillus farciminis, Lactobacillus fermentum, Lactobacillus hilgardii, Lactobacillus plantarum, Weissella cibaria, Weissella confusa, Weissella kimchii, Leuconostoc citreum, Leuconostoc lactis, Pediococcus acidilactici, and Pediococcus pentosaceus. PCR amplification and gel electrophoresis were performed to verify the specificities of the designed primers. The results showed that the primer set No. 1 of 5'-aacaacaaaatcaccgcaca-3' & 5'- gtcgtcaatgttgtcgatgc-3' for phosphofructokinase amplified PCR products from 5 species of heterofermenter with different molecular weight depending on the genus. Primer set No. 8 of 5'-gcgtcgccgtctcg-3' & 5'- gcctgcggcttttcg-3' produced specific PCR products from three heterofermentative lactobacilli such as L. brevis, L. fermentum, and L. hilgardii. Primer set No. 18 of 5'-gtgacggtgctgtaggttca- 3' & 5'-gcagtcgcttacgccatatt-3' was specifically reacted to homofermentative species including L. farciminis, P. acidilactici, and P. pentosaceus. Hence, the primer sets which were developed in this study could be used as a tool for the classification and differentiation of homo- and hetero fermentative species in lactic acid fermented foods, like as kimchi.

Phosphorus (P) is an important structural component and plays critical roles in the process of energy transfer and signal transduction. Effect of low P on carbohydrate metabolism was investigated at the transcription level via transcriptome analysis using the rice 60K oligonucleotide DNA microarrays. Two-week-old rice seedlings were grown under a low (32 μM) or high (320 μM) P condition for two weeks and leaves from the seedlings were used for transcriptome analysis. Expression of genes involved in carbohydrate metabolic pathways (eg. glycolysis, sucrose degradation and starch synthesis and degradation) was most significantly affected under low P. Under low P, most genes involved in glycolysis were intensively down-regulated, genes of starch biosynthesis and degradation pathway were up- or down-regulated, and many genes involved in sucrose biosynthesis were intensively up-regulated. In leaves under low P, glucose and pyruvate levels decreased, but sucrose and starch levels increased. These results suggest that carbohydrate metabolism is adjusted primarily through comprehensive transcriptional modulation of genes involved in the carbohydrate metabolic super-pathway.