Search Results (4)

Potassium cation (K⁺) is essential for wheat (Triticum aestivum L.) growth, but the regulatory mechanisms of root response to K⁺ deficiency are not well understood. This study examines how varying durations of K⁺-deprivation affect root K⁺ transport and homeostasis in two wheat varieties, XN979 and YM68. Field pot experiments over three growing seasons showed that XN979 has significantly higher K uptake and productive efficiency than YM68 at a K fertilizer application rate of 60 kg hm⁻². Hydroponic experiments revealed that XN979 has a lower K_m (K⁺ concentrations at which 1/2 of V_max) and a higher V_max (maximum rate of K⁺ uptake) in K⁺ uptake kinetics, indicating better adaptation to K⁺-deficient environments. RNA-seq analysis after different durations of K⁺ deficiency (0, 6, 12, 24, 48 h) showed that genes encoding the Arabidopsis K⁺ Transporter 1 (AKT1) K⁺-channel in both varieties were not significantly upregulated. Instead, K⁺ transport in root primarily depended on high-affinity K⁺ (HAK) transporters. Genes encoding the Arabidopsis K⁺ Transporter 2 (AKT2) K⁺-channel in phloem cells were significantly upregulated under K⁺-deprivation. KOR1 and KOR2, encoding the Stelar K⁺ Outward Rectifier (SKOR) K⁺-channel in xylem cells, were significantly downregulated after 6 h and 12 h of K⁺-deprivation, respectively. Significant changes in the expression levels of the Calcineurin B-Like protein–CBL-Interacting Protein Kinase (CBL-CIPK) signaling system and phytohormones synthesis-related genes suggest their involvement in the root response to K⁺-deprivation. These findings clarify the regulation of wheat root responses to K deficiency. Full article

CBL-interacting protein kinases (CIPKs) play important regulatory roles in plant growth development and abiotic stress tolerance. However, the biological roles of these genes in response to low-nitrate (LN) stress in potato plants have not been determined. Here, we reported that StCIPK23 was expressed mainly in roots and leaves. StCIPK23 was located mainly in the cell membrane, nucleus, and cytoplasm. Further research suggested that, compared with wild-type (WT) plants, StCIPK23-overexpressing plants were taller and had significantly greater nitrate and ammonium nitrogen contents under LN stress. StCIPK23 overexpression can increase StAT, StNRT2.1, StNR, StGS1-3, and StGOGAT expression levels in StCIPK23 transgenic seedlings compared to those in WT plants under LN stress. The results of yeast two-hybrid and luciferase complementation imaging experiments suggested that StCIPK23 could interact with StCBL3. Real-time reverse transcription–PCR revealed the StCIPK23 expression level peaked at 6 h and the StCBL3 expression level peaked at 9 h in the roots under LN stress. In conclusion, we found that StCIPK23 and StCBL3 form a complex to regulate the expression of key genes in the nitrogen metabolism pathway to improve LN tolerance in potato plants. Full article

CBL-interacting protein kinases 3/9/23/26 (CIPK3/9/23/26) are central regulation components of magnesium ion homeostasis. CBL2/3 interacts with CIPK3/9/23/26, which phosphorylates their downstream targets, suggesting that protein phosphorylation is a key factor influencing the maintenance of cellular magnesium homeostasis in higher plants. The cipk3/9/23/26 quadruple mutant is very sensitive to high levels of magnesium. In this study, TMT quantitative phosphoproteomics were used to compare the global variations in phosphoproteins in wild type and cipk3/9/23/26 quadruple mutant seedlings of Arabidopsis thaliana, and 12,506 phosphorylation modification sites on 4537 proteins were identified, of which 773 phosphorylated proteins exhibited significant variations at the phosphorylation level under magnesium sensitivity. Subsequently, we used bioinformatics methods to systematically annotate and analyze the data. Certain transporters and signaling components that could be associated with magnesium sensitivity, such as ATP-binding cassette transporters and mitogen-activated protein kinases, were identified. The results of this study further our understanding of the molecular mechanisms of CIPK3/9/23/26 in mediating magnesium homeostasis. Full article

Meloidogyne incognita and Meloidogyne graminicola are root-knot nematodes (RKNs) infecting rice (Oryza sativa L.) roots and severely decreasing yield, whose mechanisms of action remain unclear. We investigated RKN invasion and development in rice roots through RNA-seq transcriptome analysis. The results showed that 952 and 647 genes were differently expressed after 6 (invasion stage) and 18 (development stage) days post inoculation, respectively. Gene annotation showed that the differentially expressed genes were classified into diverse metabolic and stress response categories. Furthermore, phytohormone, transcription factor, redox signaling, and defense response pathways were enriched upon RKN infection. RNA-seq validation using qRT-PCR confirmed that CBL-interacting protein kinase (CIPK) genes (CIPK5, 8, 9, 11, 14, 23, 24, and 31) as well as brassinosteroid (BR)-related genes (OsBAK1, OsBRI1, D2, and D11) were altered by RKN infection. Analysis of the CIPK9 mutant and overexpressor indicated that the RKN populations were smaller in cipk9 and larger in CIPK9 OX, while more galls were produced in CIPK9 OX plant roots than the in wild-type roots. Significantly fewer numbers of second-stage infective juveniles (J2s) were observed in the plants expressing the BR biosynthesis gene D2 mutant and the BR receptor BRI1 activation-tagged mutant (bri1-D), and fewer galls were observed in bri1-D roots than in wild-type roots. The roots of plants expressing the regulator of ethylene signaling ERS1 (ethylene response sensor 1) mutant contained higher numbers of J2s and developed more galls compared with wild-type roots, suggesting that these signals function in RKN invasion or development. Our findings broaden our understanding of rice responses to RKN invasion and provide useful information for further research on RKN defense mechanisms. Full article