Transgenic evaluation of antimicrobial peptides (AMPs) has so far has identified a modified thionin (Mthionin) that conferred resistance against HLB and canker when over-expressed in Carrizo plants (Hao et al, 2016 Front Plant Sci.). From the same transgenic Carrizo population, we screened another 37 positive plants by PCR validation of gene insertion and documented Mthionin transcript level of each plant by RT-qPCR. Multiple high, intermediate and low transgene expressing plants were selected and propagated using stem cuttings (a total of 250 cuttings). Once established these plants will be tested as rootstocks with sweet orange and grapefruit scions. compared with wild type Carrizo as a rootstock. An antibody has been developed for specific detection of Mthionin and a second to detect both Mthionin and citrus native thionin. Currently, we are evaluating binding capacity and sensitivity of these antibodies to antigen peptides and to full-length proteins (expressed by E.Coli). Later the antibodies will be used for access expression level and mobility of thionin protein between root stock and scion. Two additional Mthionin chimera genes (2nd generation of AMPs), Mthionin-D2A21 and Mthionin-lipid binding protein (LBP), have been used to produce transgenic Carrizo and Hamlin. So far we have obtained a number of transgenic Carrizo plants and made a propagation of about 100 for each transgene. These plants will be used for initial evaluation of HLB resistance through no choice ACP feeding inoculation and promising lines will be further propagated for field tests. The 3rd generation of AMPs includes two variants of modified citrus thionin genes combined with citrus LBP. Transformation of these two chimeras into Carrizo and Hamlin is underway. So far we have obtained a number of Carrizo regenerations. We are also in the process of the evaluation of HLB resistance in several Hamlin transgenic lines: we graft propagated transgenic Hamlin expressing Mthionin, D4E1 linker Mthionin, and LuxI, with wild type scion as the controls. These plants are established and inoculated by no choice feeding from 9 to 12 month ago. The bacterial titer tests showed that only very few plants were HLB positive, indicating the inoculation procedure was not successful. These plants were uniformly trimmed for new flush growth and will soon be re-inoculated with our improved protocols. The previous generations of transgenics remain in testing in the greenhouse and field.