The function of the phytoplasma effector SWP12 depends on the properties of two key amino acids.

Phytoplasmas are insect-borne bacterial pathogens capable of secreting effectors into host cells and interfering with host plant defense response processes. Previous studies have found that the Candidatus Phytoplasma tritici effector SWP12 binds to and destabilizes the wheat transcription factor TaWRKY74, increasing wheat susceptibility to phytoplasmas. Here, we used a Nicotiana benthamiana transient expression system to identify two key functional sites of SWP12 and screened a series of truncated mutants and amino acid substitution mutants to determine whether they inhibit Bax-induced cell death. Using a subcellular localization assay and online structure analysis websites, we found that structure rather than intracellular localization probably affects the function of SWP12. D33A and P85H are two inactive substitution mutants, neither of which interacts with TaWRKY74, and P85H does not inhibit Bax-induced cell death, suppress flg22-triggered reactive oxygen species (ROS) bursts, degrade TaWRKY74, or promote phytoplasma accumulation. D33A can weakly suppress Bax-induced cell death and flg22-triggered ROS bursts and degrade a portion of TaWRKY74 and weakly promote phytoplasma accumulation. S53L, CPP, and EPWB are three SWP12 homolog proteins from other phytoplasmas. Sequence analysis revealed that D33 was conserved in these proteins, and they exhibited the same polarity at P85. Transient expression in N. benthamiana showed that these proteins could inhibit Bax-induced cell death and suppress ROS bursts. Our findings clarified that P85 and D33 of SWP12 play critical and minor roles, respectively, in suppressing the plant defense response and that they play a preliminary role in determining the functions of homologous proteins.

[Correlative study between length of first metatarsal and transfer metatarsalgia after osteotomy of first metatarsal].

OBJECTIVE: To evaluate the correlation between the length of first metatarsal, hallux valgus angle (HVA), intermetatarsal 1-2 angle (IMA1-2), plantar appearance, sesamoid position and postoperative 2-5 transfer metatarsalgia. METHODS: Retrospective analysis was performed for the clinical data of 375 cases (626 feet) undergoing osteotomy of first metatarsal with mini-incision. All cases were examined radiographically via weight-bearing and lateral views. HVA, IMA1-2 and the length of first metatarsal were measured preoperatively and postoperatively. Forefoot plantar pressure was measured during walking by Foot scan system preoperatively and postoperatively. RESULTS: After a mean follow-up period of 12-30 (18.5 ± 6.8) months, all patients had satisfactory bone healing without late healing or disunion. There were superficial wound infection (n = 1, 1 foot) and suture reaction (n = 1, 1 foot). HVA was 7.18° ± 4.55° postoperatively and corrected by 30.54°; IMA1-2 5.07° ± 1.70° and corrected by 12.33°. The number of shorting of first metatarsal during 0-2 mm was 424 feet, there was 1 case of transfer metatarsalgia at rays 4; the number during 2-4 mm was 186 feet, there were 5 cases of transfer metatarsalgia at rays 2. The center of pressure shifted laterally; the number during 2-4 mm was 16 feet, there were 4 cases of transfer metatarsalgia at rays 2 and 3. The center of pressure shifted evidently medially; the shorting of first metatarsal was 4.8 ± 0.46 mm. A negative correlation was found between length of metatarsal and transfer metatarsalgia at rays 2 and 3. No correlation existed between transfer metatarsalgia at rays 2 and 5, HVA and IMA1-2. A positive correlation existed between HVA decrease and patient satisfaction with their postoperative foot alignment. There was no correlation between lengthening of metatarsal and IMA1-2 decrease. CONCLUSION: Length preservation of first metatarsal seems to prevent the postoperative transfer metatarsalgia on second and third rays. The shorting of first metatarsal should be no more than 2 mm.