This document provides information about the kingdom Stramenopila and some key phyla within it. It discusses the phyla Hypochytriomycota, Labyrinthulomycota, and Oomycota. For Oomycota, it describes the characteristics of the phylum and provides details about some important classes, orders, families, and genera within it like Phytophthora and Pythium. It compares the differences between Phytophthora and Pythium.

1. BIHAR AGRICULTURE UNIVERSITY
BAC ,SABOUR BHAGALPUR
DEPARTMENT PLANTPATHOLOGY
NAME : KUMAR SUMAN
ROLL NO: M-PATH-00746-BAC- 2020/2021
COURSE TITLE: PL PATH 501 MYCOLOGY
SUBMITTED TO: Dr.Chanda kushwaha Ma’am
(Dept of plant pathology)

2. KINGDOM STRAMENOPILA
 Include diatoms chrysophytes ,brown alge and some protozoa.
 Phyla of fungal like organisam
1) hypochytriomycota
2) Labyrinthulomycota
3) Oomycota
 Name means straw hair and introduced by D.J. Patterson in 1989 based on tinsel type
flagellum.
 presence of filamentous thallus in stramenopiles and fungi is evidence of convergent
evolution.
 CONVERGENT EVOLUTION: Evolution of similar feature independently in different
evolutionary linages , usually by different developmental pathway .

3. Phylum Hypochytriomycota
 occur in soil ,fresh water and marine habitats, saprotrophs or parasites on alge and fungi.
 closely related to Oomycota.
 CHARACTER
 Cell walls contain chitin and cellulose.
Thallus type similar to chytrids ( holocarpic or eucarpic).
 Zoospore with one anteriorly inserted tinsel flagellum.
Sexual reproduction poorly known
 2 families ,6 genera 23 species
 thallus

4. PHYLUM LABYRINTHULOMYCOTA
 CALLED MARINE SLIME MOLDS
Parasitic or saprotrophic
 CHARACTERISTICS
 Ectoplasmic produced by bathrosome
 Thallus covered with thin golgi scale
 Biflagellate zoospore with long , tinsel flagellum and shoter whiplash flagellum.
o Two families:
a) Labyrinthulaceae: Spindle shaped cells ,Zoospore have eyespots
b) Thraustochytriaceae: Thallus covered with scale ,zoospore lack eye spots, covered with
layer of scale .

5. PHYLUM OOMYCOTA
 Oomycota means egg fungi , and refers to the large round oogonia .
 they are filamentous which most absorb their food from the surrounding water or soil.
 Characteristics
 Produce motile zoospore ,biflagellate ,1whiplash and 1 tinsile.
 commonly called water molds, primarily pathogenic on fish and plant.
 Produce large body non septate hyphae – TRUE MYCELIUM.
 vegetative hyphae is absorptive- HAPLOID(n).
 cell wall contain cellulose and some chitin.
 Anamorphic reproduction : zoosporangium containing zoospores(n).
 Teleomorphic reproduction: male and female mating structure are produced – male
Antheridium and female – Oogonium containing an unfertilized oospore.

6. • CLASS: OOMYCETES
 Saprolegnials
 water molds
 All are aquatic
 Most are saprophytic
 Saprolegnia sp.
 A chlya sp.
 LIFE CYCLE OF SAPROLEGINIA
• Both sexual and asexual reproduction
• sexual repro- anthridium and oogonium.
• Asexual repro- primary zoospore and
secondary zoospores.
• secondary zoospores are more motile.

7. ORDER: PERNOSPORALES
FAMILY :PERONONSPORACEAE
 The most developed fungi of the class oomycetes,aquatic and terrestrial species
and obligate parasites. Biflagellate zoospores and conidia which germinate directly.
 Cell wall is made up of fibril and polyscahharides,90%wall is constituted by glucans.
 cell wall also contain amino acid and hydroxy proline.
 Mycelium of the pernosporales is well developed , consisting of coenocytic , stout
hyphae that branch freely.
 reproduction is two type :Asexual type and sexual type.
 Asexual reproduction is through zoospores.
 sexual reproduction is oogamous and take place by gametangial contact.

8. PHYTOPHTHORA
ORDER:PERNOSPORALES
FAMILY: PERNOSPORACEAE
GENUS: PHYTOPHTHORA
 Phytophthora means , the plant destroyer,water soaked, light brown lesion develops in the leaf.
 Lesion turn purplish black, rot and white fungal growth seen in affected area.
 Rotten portion emits characteristics odour.
 Life cycle is two type > Asexual reproduction and Sexual reproduction.
 The asexual reproduction takes place by sporangia which are borne on aerial Sympodially branched
sporangiophores.
 Sexual reproduction takes place by antheridia and oogonia of opposite mating.

9. ORDER:PYTHIALES
FAMILY: PYTHIACEAE
GENUS: PYTHIUM
 Saprophytic or parasitic , mycelium is intracellular.
It include amphibious and terrestrial fungi.
The mycelium consists of coenocytic hyphae , live saprophytically on dead or organic matter.
Genus Pythium reproduce by both sexual and asexual reproduction.
 Asexual reproduction take place by producing sporangia as a terminal on the somatic hyphae.
Sporangia germinate directly by germtube.
Sexual reproduction takes place by gametangial contact.
 Oogonia and antheridia are developed in close often on the same hyphae.

10.  DIFFERENCE BETWEEN PYTHIUM AND PHYTOPHTHORA
 PYTHIUM: Facultative parasite, mostly aquatic, amphibious, hypal wall contain grater protein
Appressoria and haustoria are absent. sporangiospores have somatic hyphae of
the mycelium. sporangia are either terminal or intercalary globose . zoospore are
differentiated in the vesicle, oogonial wall is colourless, smooth, and anthredia
paragynous.
 PHYTOPHTHORA : Facultative parasite , mostly terrestrial and less depend on free water for
reproduction. hypal, wall contain little amount of protein. appressoria
and haustoria is always present. sporangiophores have symbodial branch.
sporangia are always terminal,lemon shaped. Oogonial wall is brown
rough and warty. Anthredia mostly amphigynous.

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