ryvaO itsseT tyceoeHm eadH ttIneuegnm tydobaF itugdM ililt-hanuubepgaMM iillt-hanbuugpaeFM /-FSAGM /-SAGMM -SPGM -FSPG B. mori Host Response to Bb Midgut Midgut+ Malpighian tubule Integument + Fat body Head +Integument Silk gland Testis 0 0 . 5 - 3 3 . 3 - 7 6 . 1 - 0 0 . 0 7 6 . 1 3 3 . 3 0 0 . 5 tissues induced genes midgut 886 fat body 739 malpighian tube 796 hemocyte 662 integument 906 testis 1067 head 1007 A/MSG 733 ovary 402 PSG 772 % indueced tissue-specific genes % induecd tissue-specific genes 15.86 66 30.56 17.43 1 16.67 15.69 11 10.00 16.34 2 8.33 15.36 1 7.14 13.46 75 6.79 15.18 4 5.13 16.54 2 5.00 6.63 1 2.7 18.08 0 0 Figure 4. Tissues expression data on day 3 of the fifth instar of the induced genes. (a) Cluster of multiple tissues expression data of the induced genes. For details of these data, see Table S3. (b) The summary of the multiple tissues expression of the induced genes. doi:10.1371/journal.pone.0008098.g004 after Bb infection are consistent with those of Neill and Ridpath for ubiquitous viral pathogen of cattle bovine viral diarrhoea virus (BVDV)-infected Madin-Darby bovine kidney cells, indicating the modulation of these genes might be general after pathogens infection [35]. Pyrimidine and purine metabolism. In vivo, nucleic acid metabolism has an important role [36]. Disruption of an organism’s nucleic acid metabolism can cause serious diseases such as gout in humans [37]. Twenty-two genes involved in pyrimidine metabolism pathway were induced after the infection (Fig. 5), including 11 types of enzymes that can catalyze at least 11 typical biochemical reactions (Table S1). The largest subfamily was that of RNA uridylyltransferase (EC 2.7.7.6), containing nine members. The second largest subfamily was DNA PLoS ONE | www.plosone.org 5 December 2009 | Volume 4 | Issue 12 | e8098