Journal of Plant Biology

, 54:269

Quantitative Measurements of Xanthomonas Oryzae pv. Oryzae Distribution in Rice Using Fluorescent-Labeling

  • Kazunari Nozue
  • Chang-Jin Park
  • Pamela C. Ronald
Original Research


The rice host sensor, XA21, confers robust resistance to most strains of Xanthomonas oryzae pv. oryzae (Xoo), the casual agent of bacterial blight disease. Using in planta fluorescence imaging of Xoo strain PXO99Az expressing a green fluorescent protein (Xoo-gfp) we show that XA21 restricts Xoo spread at the point of infection. This noninvasive and quantitative method to measure spatial distribution of Xoo populations in planta facilitates detailed assessment of plant disease resistance.


Xanthomonas oryzae pv. oryzae, GFP, Oryza sativa Xa21 



Xanthomonas oryzae pv. oryzae


green fluorescent protein


colony-forming unit

Supplementary material

12374_2011_9164_Fig6_ESM.jpg (16 kb)
Fig. S1

Detection of Xoo-gfp in a Kitaake and b XA21-Kitaake immediately after smear inoculation (OD = 0.5 at 600 nm). A weak Xoo-gfp fluorescence signal was observed (upper panels), consistent with a low Xoo population in leaves. Bright field images of identical leaves are shown in lower panels. A bar indicates 1 cm. A color bar indicates Xoo-gfp concentration (CFU/mm2) based on results in Fig. 2b (JPEG 15 kb)

12374_2011_9164_MOESM1_ESM.tif (2.3 mb)
High resolution image (TIFF 2378 kb)
12374_2011_9164_Fig7_ESM.jpg (13 kb)
Fig. S2

Microscopic observation of Xoo-gfp distribution in rice leaves 4 days after smear inoculation. a The surface of XA21-Kitaake leaves inoculated with Xoo-gfp was visualized using a Zeiss Axiophot fluorescence microscope (Jena, Germany). Xoo cells were observed mainly around the bases of broken trichomes (arrows). b Kitaake leaves inoculated with Xoo-gfp. Xoo cells spreads throughout the xylem vessel (arrowhead) from the site of infection at a broken trichome (an arrow). Adaxial sides of leaves were observed using GFP filter set (excitation, 470/40 nm; beam splitter, FT495 nm, emission, 525/50 nm) at ×100 magnification as described in Materials and methods. Bars in a and b, 100 μm (JPEG 12 kb)

12374_2011_9164_MOESM2_ESM.tif (4.3 mb)
High resolution image (TIFF 4451 kb)
12374_2011_9164_Fig8_ESM.jpg (13 kb)
Fig. S3

Xoo-gfp detection in stem and sheath tissues in Kitaake and XA21-Kitaake plants after smear inoculation. Xoo-gfp was inoculated on the stem and sheath tissue. a Fluorescence image and b bright image were obtained from identical leaves of Kitaake and XA21-Kitaake with Xoo-gfp or mock inoculation. Xoo-gfp failed to spread out from inoculated area (shown as a bracket) in XA21-Kitaake. A bar indicates 1 cm. L leaf blade, S sheath and stem, P panicle. An arrowhead indicates the nodes. A color bar indicates Xoo-gfp concentration (CFU/mm2) based on results in Fig. 2b. Kit Kitaake, Xa21-Kit XA21-Kitaake (JPEG 13 kb)

12374_2011_9164_MOESM3_ESM.tif (1.2 mb)
High resolution image (TIFF 1219 kb)


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Copyright information

© The Botanical Society of Korea 2011

Authors and Affiliations

  • Kazunari Nozue
    • 1
  • Chang-Jin Park
    • 2
  • Pamela C. Ronald
    • 2
  1. 1.Department of Plant Biology, College of Biological SciencesUniversity of California, DavisDavisUSA
  2. 2.Department of Plant Pathology, College of Agricultural and Environmental SciencesUniversity of California, DavisDavisUSA

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