cgi-bin/community/feature/200510.pl

   1 use strict;
   2 use CXGN::Page;
   3 my $page=CXGN::Page->new('200510','Teri Solow');
   4
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  31 $page->header('The Jahn Lab', undef, $stylesheet);
  32 print<<END_HEREDOC;
  33
  34 <center>
  35 <h1>The Jahn Lab</h1>
  36 </center>
  37
  38 <p class="footnote"><img src="/static_content/community/feature/200510-1.jpg" border="4" style="border-color: #000000" width="800" height="600" alt="Jahn Lab" /><br />
  39 </p>
  40
  41 <p style="border-bottom: 0px">The research in our group focuses on gene discovery, the analysis of
  42 genome structure and function and the relevance of this information for the
  43 improvement of useful plants.  Work in our program includes fundamental
  44 studies of the relationship between model species and less well-
  45 characterized crop species, the release of varieties and advanced breeding
  46 lines, development of improved selection strategies, and research on the
  47 genetics of disease resistance and fruit quality.  Specifically, a major
  48 effort in the lab is to demonstrate the extent to which results from a
  49 leading plant model, tomato, are relevant to the related, but much less
  50 well-characterized genus, <em>Capsicum</em>, the garden pepper. Towards this end we
  51 have developed a detailed comparative genetic map for the Solanaceae now
  52 defining the broadest comparative genetic system in the dicots. We have
  53 used this tool to identify candidates for traits with simple and
  54 quantitative inheritance and to assess the relationships between genes in
  55 tomato and pepper that affect similar or related traits. Further studies
  56 are focusing on traits considered distinctive</p>
  57
  58 <p class="footnote" style="float:right; width:375px; text-align:center;"><img src="/static_content/community/feature/200510-2.gif" border="4" style="border-color: darkgreen" width="333" height="229" alt="Different species and varieties of pepper" /><br />
  59 Different species and varieties of pepper for a genus, e.g., pungency.
  60 </p>
  61
  62 <p style="border-top:0px">Finally, the Solanaceae have afforded a unique
  63 glimpse of the organization of resistance genes in plant genomes.  We have
  64 shown that despite co-evolutionary forces in host/pathogen interactions,
  65 disease resistance genes represent ancient lineages in plants and that
  66 resistance pathways may be very highly conserved. We also have extensive
  67 gene discovery and breeding activities that integrate classical and
  68 molecular methods for generating and selecting desirable genetic
  69 variability, primarily focused on the identification of new sources of
  70 biotic and abiotic stress resistance from wild accessions and related
  71 species in cucurbits, <em>Phaseolus</em> and pepper. The Public Seed Initiative is
  72 an outreach activity based on an alliance of public sector researchers and
  73 non-profit groups interested in improving the dissemination and utilization
  74 of public plant varieties and crop genetic diversity.</p>
  75
  76 <p>Pungency in pepper pods is a consequence of accumulation of the alkaloid
  77 capsaicin (shown below) and its analogs. The biosynthesis of capsaicin is
  78 restricted to the genus <em>Capsicum</em> and results from the acylation of an
  79 aromatic moiety, vanillylamine, by a branched chain fatty acid. Apart from
  80 portions of the biosynthetic pathway common to other primary metabolic
  81 pathways, the remainder of the pathway remains unknown. One of the major
  82 projects within our group focuses on capsaicin biosynthesis and the genes
  83 that define and regulate the pathway.</p>
  84
  85 <p class="footnote" style="float:right; width:440px; text-align:center;"><img src="/static_content/community/feature/200510-3.gif" border="0" width="398" height="103" alt="Molecular structure of capsaicin" /><br />
  86 Molecular structure of capsaicin
  87 </p>
  88
  89 <p>Due to the popularity and familiarity of products containing capsaicin
  90 there is rapidly growing economic significance in a wide array of food
  91 products, in medicine, industry, law enforcement, and pest control (it has
  92 become a leading insect protectant in organic agriculture and is the active
  93 ingredient in many of the most effective deer and rodent repellents). Considering the importance of this pathway, it
  94 is surprising that relatively little is known, particularly at the
  95 molecular level, concerning the molecular genetics, biosynthesis,
  96 subcellular localization and cellular structures required for pungency
  97 accumulation in peppers. The recent cloning and initial characterization of
  98 <em>Pun 1</em> (formerly known as <em>C</em>) allows for new insight into capsaicin
  99 biosynthesis and accumulation. <em>pun 1</em> was first reported nearly 100 years
 100 ago and was shown to be epistatic to all other pungency-related genes
 101 (Webber, 1911). At present, the <em>pun1</em> allele is the only confirmed mutation
 102 that has a qualitative affect on the presence/absence of capsaicinoids
 103 (Blum et al., 2002 and references therein).  Further characterization of
 104 <em>Pun 1</em>, as well as other candidates implicated in pungency is currently
 105 underway.</p>
 106
 107 <p>Another area of research in our lab is potyvirus resistance.  Mutations
 108 in the eIF4E homolog, encoded at the <em>pvr1</em> locus, result in broad-spectrum
 109 potyvirus resistance conferred by <em>pvr1</em> resistance allele in Capsicum, a
 110 gene widely deployed in agriculture. Point mutations in recessive
 111 resistance genes, <em>pvr1</em>, <em>pvr1<sup>1</sup></em> and <em>pvr1<sup>2</sup></em>, grouped to similar regions of the
 112 <em>eIF4E</em> gene and were predicted by protein homology models to cause
 113 conformational shifts in the encoded proteins. While the protein encoded by
 114 <em>pvr1<sup>+</sup></em> interacts strongly, proteins translated from all three resistance
 115 alleles (<em>pvr1</em>, <em>pvr1<sup>1</sup></em> and <em>pvr1<sup>2</sup></em>) failed to bind VPg from either strain of
 116 TEV in a yeast two hybrid assay.  This failure to bind correlates with
 117 resistance, suggesting that interruption of the interaction between VPg and
 118 this eIF4E paralog may be necessary, but is not sufficient for potyvirus
 119 resistance <em>in vivo</em>.  Among the three resistance alleles, only the <em>pvr1</em>
 120 gene product fails to bind m<sup>7</sup>-GTP cap-analog columns, suggesting that
 121 disrupted cap-binding is not required for potyvirus resistance.</p>
 122
 123 <p class="footnote" style="float:left; width:350px; text-align:center;">
 124 <img src="/static_content/community/feature/200510-5.gif" border="4" style="border-color: #000000" width="281" height="215" alt="Pepper infected with Tobacco Etch Virus" />
 125 <br />
 126 Uninfected pepper plant
 127 </p>
 128
 129 <p class="footnote" style="float:right; width:350px; text-align:center;">
 130 <img src="/static_content/community/feature/200510-4.gif" border="4" style="border-color: #000000" width="280" height="215" alt="Uninfected pepper plant" />
 131 <br />
 132 Pepper infected with Tobacco Etch Virus
 133 </p>
 134
 135 <br clear="all" />
 136
 137 <div style="float:left; width:250; text-align:left;">
 138 <h2>Contact Information</h2>
 139 <p>
 140 Molly Jahn<br />
 141 Professor<br />
 142 313 Bradfield Hall<br />
 143 Plant Breeding and Genetics<br />
 144 Cornell University<br />
 145 Ithaca, NY 14853<br />
 146 <a href="mailto:mmj9\@cornell.edu">mmj9\@cornell.edu</a><br />
 147 607.255.8147<br />
 148 607.255.6683 (fax)<br />
 149 </p>
 150 </div>
 151
 152 <p class="footnote" style="float:right; width:400px; text-align:center;"><img src="/static_content/community/feature/200510-6.gif" border="0" width="179" height="164" alt="Swirly image" /><br />
 153 </p><br clear="all" />
 154
 155 <h2>Selected Publications</h2>
 156
 157 <p class="bibliography">
 158 Kang, B.-C., I.H. Yeam, J.D. Frantz, and M.M. Jahn.  2005. Mutations in
 159     translation initiation factor eIF4E that confer resistance to potyvirus
 160     infection abolish interaction with Tobacco etch virus VPg in a non-
 161     specific manner.  Plant J. 42:392-405.
 162 </p>
 163
 164 <p class="bibliography">
 165 Stewart, C. Jr., B.-C. Kang, K. Liu, M. Mazourek, S. Moore, M.M. and Jahn.
 166     2005. The Pun1 gene for pungency in pepper encodes a putative
 167     acyltransferase. Plant J. 42:675-688.
 168 </p>
 169
 170 <p class="bibliography">
 171 Liu, K., B.-C. Kang, H. Jiang, C.B. Watkins, T.L. Setter and M.M. Jahn.
 172     2005. Identification and characterization of an auxin-responsive GH3-
 173     like gene in pepper fruit development. (accepted Plant Mol. Biol.).
 174 </p>
 175
 176 <p class="bibliography">
 177 E. A. Quirin, E. Ogundiwin, J.P. Prince, M. Mazourek, M. O. Briggs, T. S.
 178     Chlanda, K.T. Kim,  M. Falise, B.-C. Kang, and M.M. Jahn. 2005.
 179     Development of sequence characterized amplified region (SCAR) primers
 180     for the detection of Phyto.5.2, a major QTL for resistance to
 181     Phtophthora capsici Leon. in pepper .Theor. Appl. Genet. 110(4):605-12.
 182 </p>
 183
 184 <p class="bibliography">
 185 Kang, B.-C., and I. H. Yeam, and M.M. Jahn. 2005. Virus resistance genes.
 186       Ann.  Rev. of Phytopath. E. pub. May 2. 43:581-621.
 187 </p>
 188
 189 <p class="bibliography">
 190 Porch, T.G., M.H. Dickson, M. Long, D.R. Viands, and M.M. Jahn. 2005.
 191     General combining ability effects for reproductive heat tolerance in
 192     snap bean. J. Agriculture U. Puerto Rico 88(3-4):x-x.
 193 </p>
 194
 195 <p class="bibliography">
 196 Qian C.T., M.M. Jahn, J.E. Staub, X.-D. Luo and J.F. Chen. 2005.  Meiotic
 197 chromosome
 198       behavior in an allotriploid derived from an amphidiploid x diploid
 199     mating in Cucumis. accepted Plant Breeding
 200 </p>
 201
 202 <p class="bibliography">
 203 Henning, M.J, H.M. Munger and M.M. Jahn.  2005.  'Hannah's Choice F1' : A
 204     new muskmelon hybrid with resistance to powdery mildew, Fusarium race 2
 205     and potyviruses. HortScience in press.
 206 </p>
 207
 208 <p class="bibliography">
 209 Henning, M.J, H.M. Munger and M.M. Jahn.  2005. 'PMR Delicious 51':  An
 210     improved open-pollinated melon with resistance to powdery mildew.
 211     HortScience 40(1):261-262.
 212 </p>
 213
 214 <p class="bibliography">
 215 Paran, I., J. Rouppe van der Voort, V. Lefebvre, M.M. Jahn, L. Landry, R.
 216     van Wijk, H. Verbakel, B. Tanyolac, C. Caranta, A. Ben Chaim, K.D.
 217     Livingstone, A. Palloix and J. Peleman.  2004. An integrated genetic
 218     map of pepper. Molecular Breeding 13:251-261.
 219 </p>
 220
 221 <p class="bibliography">
 222 Chen, J., X. Luo, C. Qian, M.M. Jahn, J.E. Staub, F. Zhuang, Q. Lou and G.
 223     Ren.  2004. Cucumis monosomic alien addition lines:  morphological,
 224     cytological and RAPD analysis.  TAG 108:1343-1348.
 225 </p>
 226
 227 <p class="bibliography">
 228 Alba, R., Z. Fei, P. Payton, Y. Liu, S.L. Moore, P. Debbie, J.S. Gordon,
 229      J.K.C. Rose, G. Martin, S.D. Tanksley, M. Bouzayen, M.M. Jahn and J.
 230      Giovannoni.  2004.  ESTs, cDNA microarrays and gene expression
 231      profiling:  tools for dissecting plant physiology and development.
 232      Plant J. 39:697-714
 233 </p>
 234
 235 <p class="bibliography">
 236 Rose, J.K.C., S. Bashir, JJ Giovannoni, MM Jahn and R.S. Saravanan.  2004.
 237     Tackling the plant proteome:  practical approaches, hurdles and
 238     experimental tools.  Plant J 39:715-733.
 239 </p>
 240
 241 <p class="bibliography">
 242 Nelson, R.J., R. Naylor and M.M. Jahn.  2004. The role of genomics research
 243     in the improvement of orphan crops. Crop Science 44:1901-1904.
 244 </p>
 245
 246 END_HEREDOC
 247 $page->footer();