Looking into the high potassium demand and stress imposed on potato crops, the present study was carried out to select cold- and desiccation-tolerant potassium-solubilizing bacteria (KSB) for improving the growth and potassium acquisition in potato. A total of 25 KSB isolated from potato rhizosphere on modified Aleksandrov’s agar were screened for K solubilization at different time intervals, tolerance to low temperature and desiccation, and K solubilization under these stresses. Two potential KSB strains identified by 16S rRNA gene sequencing were tested on potato in pots and in fields. The isolates showed potassium solubilization index ranging from 1.1 to 4.4 on modified Aleksandrov’s agar and the solubilization in liquid medium varying from 6.0 to 16.7 µg K/ml on ninth day of incubation. The isolates were able to grow at 4 °C, and at 20% (−0.67 MPa) and 40% (−1.78 MPa) PEG 6000. The isolates also solubilized K in the presence of these stresses, although the solubilization was lower in the presence of low temperature (4 °C) and at 20% and 40% PEG 6000. Two potential KSB strains identified as Pantoea agglomerans PR2KSB1 and Pseudomonas sp. PR2KSB6 significantly affected the growth and K content of potato grown in pots under greenhouse conditions over the uninoculated control with the highest improvement shown by the combined application of PaPR2KSB1+PspPR2KSB6. Under field conditions, the combined application of N100P100K100+PaPR2KSB1+PspPR2KSB6 resulted in 12.3% increased tuber yield, 8.4% increased haulm yield, 12.3% increased tuber K content and 4.6% increased soil available K content over the control treatment N100P100K100. The plant growth and yield observed with the treatment N100P100K75+PaPR2KSB1+PspPR2KSB6 was statistically at par with that obtained with the treatment N100P100K100 indicating a saving of 25% K fertilizer with the application of Pantoea agglomerans PR2KSB1 and Pseudomonas sp. PR2KSB6. The results indicated that the stress-tolerant KSB PaPR2KSB1 and PspPR2KSB6 could be used as K-solubilizing bacterial inoculants with reduced dose of K fertilizer for sustainable agriculture.

Cold- and Desiccation-tolerant Potassium-solubilizing Bacteria Enhance Growth, Yield and Potassium Availability in Solanum tuberosum L.

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发表日期：

2026年6月19日

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Amandeep Kaur,
Loveena Pathak,
Pratibha Vyas,
Sandeep Sharma

摘要

Looking into the high potassium demand and stress imposed on potato crops, the present study was carried out to select cold- and desiccation-tolerant potassium-solubilizing bacteria (KSB) for improving the growth and potassium acquisition in potato. A total of 25 KSB isolated from potato rhizosphere on modified Aleksandrov’s agar were screened for K solubilization at different time intervals, tolerance to low temperature and desiccation, and K solubilization under these stresses. Two potential KSB strains identified by 16S rRNA gene sequencing were tested on potato in pots and in fields. The isolates showed potassium solubilization index ranging from 1.1 to 4.4 on modified Aleksandrov’s agar and the solubilization in liquid medium varying from 6.0 to 16.7 µg K/ml on ninth day of incubation. The isolates were able to grow at 4 °C, and at 20% (−0.67 MPa) and 40% (−1.78 MPa) PEG 6000. The isolates also solubilized K in the presence of these stresses, although the solubilization was lower in the presence of low temperature (4 °C) and at 20% and 40% PEG 6000. Two potential KSB strains identified as Pantoea agglomerans PR₂KSB₁ and Pseudomonas sp. PR₂KSB₆ significantly affected the growth and K content of potato grown in pots under greenhouse conditions over the uninoculated control with the highest improvement shown by the combined application of PaPR₂KSB₁+PspPR₂KSB₆. Under field conditions, the combined application of N₁₀₀P₁₀₀K₁₀₀+PaPR₂KSB₁+PspPR₂KSB₆ resulted in 12.3% increased tuber yield, 8.4% increased haulm yield, 12.3% increased tuber K content and 4.6% increased soil available K content over the control treatment N₁₀₀P₁₀₀K₁₀₀. The plant growth and yield observed with the treatment N₁₀₀P₁₀₀K₇₅+PaPR₂KSB₁+PspPR₂KSB₆ was statistically at par with that obtained with the treatment N₁₀₀P₁₀₀K₁₀₀ indicating a saving of 25% K fertilizer with the application of Pantoea agglomerans PR₂KSB₁ and Pseudomonas sp. PR₂KSB_6. The results indicated that the stress-tolerant KSB PaPR₂KSB₁ and PspPR₂KSB₆ could be used as K-solubilizing bacterial inoculants with reduced dose of K fertilizer for sustainable agriculture.