Call Prefix : PR-T

Call Suffix : 2025

Call Cutter : D - CrSc 5

Location : SEARCA Library

Format : Printed

Publisher : Can Tho University

Publication Date : 2025

Publication Place : Vietnam

Summary : Salt intrusion has caused adverse effects on nutrient uptake, growth, and yield of rice plants in the Mekong Delta, Vietnam. The study was aimed to isolate, screen, identify phosphorus (P)-solubilizing purple non-sulfur bacteria (PNSB) from salinity rice paddy field, identification of the basis for a proof of selected P-dissolving PNSB and to evaluate the effects of P-solubilizing purple non-sulfur bacteria (PSPNSB) C. sphaeroides on dissolving insoluble P forms, P uptake, growth, and yield of rice planted in salinity soil under greenhouse and field conditions. In the result, 46 isolates of PNSB were collected from 21 soil samples and 21 water samples in communes of Tran De, Hoa Tu, and My Tu Can Tho City. Among them, there were four PNSB isolates that could solubilize P, which were identified by the 16S rDNA method as Cereibacter sphaeroides at 100% similarity. The four selected isolates (ST16, ST26, ST27, and ST32) dissolved 32.7 - 60.8 mg P/L from A1-P, 30.6 - 81.7 mg P/L from Fe-P and 22.8 - 36.3 mg P/L from Ca-P in both microaerobic light and aerobic dark conditions. Moreover, these bacterial strains were potent in providing nitrogen, IAA, ALA, and EPS. Siderophores are considered one of the basics for a proof of P-solubilizing PNSB, siderophores (8.53 - 55.3%) and phosphate solubilization index were 2,50-3,17 A1-P, 8,50-20,7 Fe-P va 2,17 - 2,56 Ca-P. The genes that solubilize inorganic P were pqqB, pqqE, pstB, GDH, gcd, ppk, phnU, phn V, and organic P solubilizing genes included appA, phoB, phoU. The experiment was completely randomized in blocks with two factors and four replications under greenhouse conditions, soils collected from Mekong Delta areas such as Tri Phai - Ca Mau, Hoa Tu - Can Tho, Dong Thai - An Giang, Thanh Phong and Long Hoa - Vinh Long. Factor A was the rates of fertilizing chemical P, 0, 25, 50, 75, and 100% P according to the recommendation. Factor B was the PSPNSB including the negative control, single strain of C. sphaeroides ST16 or C. sphaeroides ST26 and a mixture of them. The soluble P in soil increased by 7,20 % - 27,8% when C. sphaeroides ST16 and ST26 were supplied singly or in the mixture, leading to the increase in total P uptake in rice by 16,7% - 70,5%, in two continuous crops. Moreover, the growth and yield components of rice were also improved, leading to an increase in rice grain yield by 7,20% - 46,6%. Moreover, supplying the C. sphaeroides ST16 and ST26 or their mixture decreased by 50% - 100% P, but still ensured the rice grain yield. The field experiment in Thanh Thoi An - Can Tho was designed in a completely randomized blocks and four replications under field conditions. Treatments were (1) PNSB combined with 0% P fertilizer, (2) PNSB combined with 25% P fertilizer, (3) recommended P fertilizer 100% P, (4) according to application of farmer formula fertilizer. The soluble P in soil increased by 3,30-5,00 mg/kg due to the P solubilization of PNSB, leading to the reduced contents of Fe-P by 39,3 - 44,7 mg/kg, Ca-P by 11,6 - 13,8 mg/kg and A1-P by 8,20 - 8,80 mg/kg in soil. Noticeably, use of Cereibacter sphaeroides combined with 25% P improved growth, yield components and reduced up to 75% P, but maintained the rice grain yield.