Post harvest diseases fruits and vegetables - Xavier University ...

More documents

Recommendations

Info

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE Chemical Control 185 since the end of the 20^^ century. However, the role of plant lectins is still not well defined and understood. One of the theories proposed hypothesizes that lectins act as recognition determinants in the formation of symbiotic relations between leguminous plants and nitrogen-fixing bacteria, a process of great importance in agriculture and in the nitrogen cycle of terrestrial life. According to a second hypothesis, these lectins can play a role in the defense of plants against various animals, as well as against phytopathogenic fungi (Sharon, 1997). Interactions of fungal hyphae with lectins were first demonstrated by Mirelman et al. (1975), who found that wheat germ agglutinin (WGA), which is specific to chitin oligosaccharides, binds to hyphal tips and hyphal septa of Trichoderma viride - a fungus with a chitinous hyphal surface. This interaction resulted in the inhibition of hyphal growth and spore germination. Based on these findings it was suggested that WGA has a role in the protection of wheat seedlings against chitin-containing fungi. To assess whether the binding of lectins to fungal surfaces and their inhibiting effects on fungal growth are general phenomena, Barkai-Golan et al. (1978) investigated the interaction of several lectins, characterized by differing sugar specificities, with various fungi belonging to different taxonomic groups. WGA was found to bind to young hyphal walls of all the fungi examined except for the chitinless Phytopthora citrophthora (Table 11). Soybean agglutinin (SBA), specific for D-galactose and N-acetyl-D-galactose, and peanut agglutinin (PNA), specific for D-galactose, were found to bind those fungi that contain galactose residues in their chitinous cell walls. Among these were several species of Penicillium and Aspergillus. Other fungi, such as Geotrichum candidum, Botrytis cinerea and Fusarium moniliforme, exhibited binding with SBA alone. The abilities of SBA and PNA to bind to fungal surfaces of Penicillium and Aspergillus species is in good agreement with the presence of galactose reported in some species of these genera, such as Penicillium digitatum and P. italicum (Grisaro et al., 1968) or Aspergillus niger (Bardalaye and Hordin, 1976). The binding of fungi to concanavalin A (Con A) is more difficult to account for since this lectin reacts only poorly with p-linked glucans and with chitin (Sharon and Lis, 1989). It is possible, however, that a positive reaction with Con A indicates the presence of small quantities of a-linked D-glucose (or D-mannose) residues on the fungal surface (Barkai-Golan et al., 1978). http://arab2000.forumpro.fr
FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE 186 Postharvest Diseases of Fruits and Vegetables TABLE 11 Binding of different lectins to fungal cell walls^ Fungus species and taxonomic group Phycomycetes Zygomycetes Rhizopus stolonifer Ehr. Mucor sp. Oomycetes Phytophthora citrophthora (Sm. et Sm.) Leon. Ascomycetes Pleospora herbarum (Pers.) Raben. Sclerotinia sclerotiorum (Lib.) de By. Basidiomycetes Rhizoctonia solani Kuhn Sclerotium rolfsii Sacc. Deuteromycetes Penicillium italicum Wehm. P. expansum Link P. citrinum Thorn P. digitatum Sacc. Chemical Lectin^ category2 wGA SEA PNA ConA Chitosan-chitin Cellulose-P-glucan Chitin-P-glucan Chitin-P-glucan Chitin-P-glucan + = marked binding; ± = moderate to weak binding; - = no binding 1 Reproduced from Barkai-Golan et al. (1978) with permission of Springer- Verlag GmbH & Co. KG. 2 As proposed by Bartnicki-Garcia, 1968 3 WGA = wheat germ agglutininm; SBA = soybean agglutinin; PNA = peanut agglutinin; ConA = concanvalin A "^ Binding confined to thin hyaline hyphae http://arab2000.forumpro.fr + + - + + -H -H + + + ± - -1- ± ± ± ± - -H ± ± ± ± + + + - + + + 4- ±
Page 1 and 2:
FREEDOM PALESTINE FREEDOM PALESTINE
Page 3 and 4:
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148: FREEDOM PALESTINE FREEDOM PALESTINE
Page 197: FREEDOM PALESTINE FREEDOM PALESTINE
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Page 297 and 298:
Page 299 and 300:
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Page 309 and 310:
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317 and 318:
Page 319 and 320:
Page 321 and 322:
Page 323 and 324:
Page 325 and 326:
Page 327 and 328:
Page 329 and 330:
Page 331 and 332:
Page 333 and 334:
Page 335 and 336:
Page 337 and 338:
Page 339 and 340:
Page 341 and 342:
Page 343 and 344:
Page 345 and 346:
Page 347 and 348:
Page 349 and 350:
Page 351 and 352:
Page 353 and 354:
Page 355 and 356:
Page 357 and 358:
Page 359 and 360:
Page 361 and 362:
Page 363 and 364:
Page 365 and 366:
Page 367 and 368:
Page 369 and 370:
Page 371 and 372:
Page 373 and 374:
Page 375 and 376:
Page 377 and 378:
Page 379 and 380:
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
Page 389 and 390:
Page 391 and 392:
Page 393 and 394:
Page 395 and 396:
Page 397 and 398:
Page 399 and 400:
Page 401 and 402:
Page 403 and 404:
Page 405 and 406:
Page 407 and 408:
Page 409 and 410:
Page 411 and 412:
Page 413 and 414:
Page 415 and 416:
Page 417 and 418:
Page 419 and 420:
Page 421 and 422:
Page 423 and 424:
Page 425 and 426:
Page 427 and 428:
Page 429 and 430:
Page 431:
show all

Post harvest diseases fruits and vegetables - Xavier University ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?