Image_2_Local auxin synthesis mediated by YUCCA4 induced during root-knot nematode infection positively regulates gall growth and nematode development.jpeg

Parasites and pathogens are known to manipulate the host’s endogenous signaling pathways to facilitate the infection process. In particular, plant-parasitic root-knot nematodes (RKN) are known to elicit auxin response at the infection sites, to aid the development of root galls as feeding sites for the parasites. Here we describe the role of local auxin synthesis induced during RKN infection. Exogenous application of auxin synthesis inhibitors decreased RKN gall formation rates, gall size and auxin response in galls, while auxin and auxin analogues produced the opposite effects, re-enforcing the notion that auxin positively regulates RKN gall formation. Among the auxin biosynthesis enzymes, YUCCA4 (YUC4) was found to be dramatically up-regulated during RKN infection, suggesting it may be a major contributor to the auxin accumulation during gall formation. However, yuc4-1 showed only very transient decrease in gall auxin levels and did not show significant changes in RKN infection rates, implying the loss of YUC4 is likely compensated by other auxin sources. Nevertheless, yuc4-1 plants produced significantly smaller galls with fewer mature females and egg masses, confirming that auxin synthesized by YUC4 is required for proper gall formation and RKN development within. Interestingly, YUC4 promoter was also activated during cyst nematode infection. These lines of evidence imply auxin biosynthesis from multiple sources, one of them being YUC4, is induced upon plant endoparasitic nematode invasion and likely contribute to their infections. The coordination of these different auxins adds another layer of complexity of hormonal regulations during plant parasitic nematode interaction.</p

Image_3_Local auxin synthesis mediated by YUCCA4 induced during root-knot nematode infection positively regulates gall growth and nematode development.jpeg

Parasites and pathogens are known to manipulate the host’s endogenous signaling pathways to facilitate the infection process. In particular, plant-parasitic root-knot nematodes (RKN) are known to elicit auxin response at the infection sites, to aid the development of root galls as feeding sites for the parasites. Here we describe the role of local auxin synthesis induced during RKN infection. Exogenous application of auxin synthesis inhibitors decreased RKN gall formation rates, gall size and auxin response in galls, while auxin and auxin analogues produced the opposite effects, re-enforcing the notion that auxin positively regulates RKN gall formation. Among the auxin biosynthesis enzymes, YUCCA4 (YUC4) was found to be dramatically up-regulated during RKN infection, suggesting it may be a major contributor to the auxin accumulation during gall formation. However, yuc4-1 showed only very transient decrease in gall auxin levels and did not show significant changes in RKN infection rates, implying the loss of YUC4 is likely compensated by other auxin sources. Nevertheless, yuc4-1 plants produced significantly smaller galls with fewer mature females and egg masses, confirming that auxin synthesized by YUC4 is required for proper gall formation and RKN development within. Interestingly, YUC4 promoter was also activated during cyst nematode infection. These lines of evidence imply auxin biosynthesis from multiple sources, one of them being YUC4, is induced upon plant endoparasitic nematode invasion and likely contribute to their infections. The coordination of these different auxins adds another layer of complexity of hormonal regulations during plant parasitic nematode interaction.</p

Image_1_Local auxin synthesis mediated by YUCCA4 induced during root-knot nematode infection positively regulates gall growth and nematode development.jpeg

Parasites and pathogens are known to manipulate the host’s endogenous signaling pathways to facilitate the infection process. In particular, plant-parasitic root-knot nematodes (RKN) are known to elicit auxin response at the infection sites, to aid the development of root galls as feeding sites for the parasites. Here we describe the role of local auxin synthesis induced during RKN infection. Exogenous application of auxin synthesis inhibitors decreased RKN gall formation rates, gall size and auxin response in galls, while auxin and auxin analogues produced the opposite effects, re-enforcing the notion that auxin positively regulates RKN gall formation. Among the auxin biosynthesis enzymes, YUCCA4 (YUC4) was found to be dramatically up-regulated during RKN infection, suggesting it may be a major contributor to the auxin accumulation during gall formation. However, yuc4-1 showed only very transient decrease in gall auxin levels and did not show significant changes in RKN infection rates, implying the loss of YUC4 is likely compensated by other auxin sources. Nevertheless, yuc4-1 plants produced significantly smaller galls with fewer mature females and egg masses, confirming that auxin synthesized by YUC4 is required for proper gall formation and RKN development within. Interestingly, YUC4 promoter was also activated during cyst nematode infection. These lines of evidence imply auxin biosynthesis from multiple sources, one of them being YUC4, is induced upon plant endoparasitic nematode invasion and likely contribute to their infections. The coordination of these different auxins adds another layer of complexity of hormonal regulations during plant parasitic nematode interaction.</p

Image_4_Local auxin synthesis mediated by YUCCA4 induced during root-knot nematode infection positively regulates gall growth and nematode development.jpeg

Parasites and pathogens are known to manipulate the host’s endogenous signaling pathways to facilitate the infection process. In particular, plant-parasitic root-knot nematodes (RKN) are known to elicit auxin response at the infection sites, to aid the development of root galls as feeding sites for the parasites. Here we describe the role of local auxin synthesis induced during RKN infection. Exogenous application of auxin synthesis inhibitors decreased RKN gall formation rates, gall size and auxin response in galls, while auxin and auxin analogues produced the opposite effects, re-enforcing the notion that auxin positively regulates RKN gall formation. Among the auxin biosynthesis enzymes, YUCCA4 (YUC4) was found to be dramatically up-regulated during RKN infection, suggesting it may be a major contributor to the auxin accumulation during gall formation. However, yuc4-1 showed only very transient decrease in gall auxin levels and did not show significant changes in RKN infection rates, implying the loss of YUC4 is likely compensated by other auxin sources. Nevertheless, yuc4-1 plants produced significantly smaller galls with fewer mature females and egg masses, confirming that auxin synthesized by YUC4 is required for proper gall formation and RKN development within. Interestingly, YUC4 promoter was also activated during cyst nematode infection. These lines of evidence imply auxin biosynthesis from multiple sources, one of them being YUC4, is induced upon plant endoparasitic nematode invasion and likely contribute to their infections. The coordination of these different auxins adds another layer of complexity of hormonal regulations during plant parasitic nematode interaction.</p

(A) mice were treated with DSS in the drinking water for 6 d, followed by water for 10 d

This protocol was repeated for a total of three cycles. After the last cycle, cells isolated from the colon were restimulated in vitro with PMA/ionomycin for 5 h and subjected to intracellular staining for GFP, IL-17, and Foxp3. Histograms (from left to right) report percent GFPTCR-β cell subsets in total T cells (see ), total numbers of RORγt Tαβ cells present in the organ, and the ratio of IL-17–producing to Foxp3 cells within RORγt Tαβ cells (see ). Right panels show immunofluorescence histology of a colon from a healthy or a treated mouse. Bar, 100 μm. (B) mice were infected intranasally with 100 PFUs of influenza A virus for 7 d. Cells were then isolated from the lung and processed as in A. Right panels show immunofluorescence histology of a lung from healthy or an infected mouse. Bar, 50 μm. (C) Cells were isolated from the mesenteric LNs of a 4-mo-old × mouse and processed as in A. Right panels show immunofluorescence histology of a mesenteric LN from a normal or a tumor-bearing mouse. Bar, 100 μm. Data shown are representative of at least three independent experiments. Three to four mice were analyzed per group. *, P < 0.05 as compared with control (mock-treated or WT mice).<p><b>Copyright information:</b></p><p>Taken from "In vivo equilibrium of proinflammatory IL-17 and regulatory IL-10 Foxp3 RORγt T cells"</p><p></p><p>The Journal of Experimental Medicine 2008;205(6):1381-1393.</p><p>Published online 9 Jun 2008</p><p>PMCID:PMC2413035.</p><p></p

(A and B) Flow cytometry analysis of cells isolated from the organs of 8–12-wk-old mice

Plots are gated on CD3 cells (A) or GFP CD3 cells (B). Numbers indicate mean percent cells in quadrants ± SD obtained with at least three mice. LPLs, lamina propria lymphocytes isolated from small intestine; mLN, mesenteric LNs; BM, bone marrow. (C) Immunofluorescence histology of RORγt cells in the small intestine of mice. Most RORγt cells in villi are T cells, whereas RORγt cells in cryptopatches located between crypts are CD3 LTi cells. Bar, 50 μm. (D) Expression of CD4 and CD8α by spleen GFPTCR-β and lung or GFPTCR-δ cells.<p><b>Copyright information:</b></p><p>Taken from "In vivo equilibrium of proinflammatory IL-17 and regulatory IL-10 Foxp3 RORγt T cells"</p><p></p><p>The Journal of Experimental Medicine 2008;205(6):1381-1393.</p><p>Published online 9 Jun 2008</p><p>PMCID:PMC2413035.</p><p></p

MACS-sorted naive (CD62L) CD4 T cells from the spleens of mice were stimulated in duplicates with anti-CD3 and anti-CD28 in the presence of blocking anti–IFN-γ and anti–IL-4 antibodies and the indicated cytokines or RA

After different periods of time, cells were restimulated with PMA/ionomycin for 5 h and analyzed by flow cytometry for the expression of GFP, Foxp3, IL-17, and IL-10. All plots are gated on TCR-β cells, except plots for IL-10 that are gated on GFPTCR-β cells. Numbers indicate percent cells in quadrants. Data are representative of three independent experiments.<p><b>Copyright information:</b></p><p>Taken from "In vivo equilibrium of proinflammatory IL-17 and regulatory IL-10 Foxp3 RORγt T cells"</p><p></p><p>The Journal of Experimental Medicine 2008;205(6):1381-1393.</p><p>Published online 9 Jun 2008</p><p>PMCID:PMC2413035.</p><p></p

(A) Cells isolated from the spleen and mesenteric LNs of mice were sorted into eight distinct populations based on their expression of GFP, CD3, TCR-β, TCR-δ, CD4, and CD25 (Fig

S1), and gene expression was assessed using real-time PCR. Ct values were normalized to the mean Ct of five housekeeping genes. Data are the mean of two or three independent experiments. (B) Foxp3 RORγt T cells express IL-10. Cells isolated from LNs of mice were restimulated in vitro with PMA/ionomycin for 5 h and subjected to intracellular staining for GFP, IL-17, Foxp3, and IL-10 or an isotype control. Numbers indicate percent cells in quadrants. Results are representative of at least three individual experiments.<p><b>Copyright information:</b></p><p>Taken from "In vivo equilibrium of proinflammatory IL-17 and regulatory IL-10 Foxp3 RORγt T cells"</p><p></p><p>The Journal of Experimental Medicine 2008;205(6):1381-1393.</p><p>Published online 9 Jun 2008</p><p>PMCID:PMC2413035.</p><p></p