Olmedo 138

Separalum EXPEIUENTIA 25, 1110 (1969)
J i i i k l i a u s e r Verla;;, l¡asel (Si lnveiz)
Purothionins in Aegilops-Triticiini
spp.
Purothionin was first obtained from the endosperm oíí
hexaploid ssheat {Triticnm aestivum I-.) and crystallizedl
by BALLS et al.'. This high sulphur protein nioicty oí ai
proteolipid has bactericida] and fungicida! activity 2 .
Receñí work3 ° has established tlaat the crystallizedl
material is a mixture of approximately equal amounls off
2 íonns: purothionins a and ft. Molecular wcight determinations, aniinoacid eoniposition and other properties;
indícate that the 2 forms are sery closely related 5 . \Ye:
have íound tliat both the allohexaploid T. aestivum L.
(genonies A B D) and the allotetraploid T. dunim Desí.
(genomes.-i B) synthetize the a and />' íonns 0 . This note is;
lo reporl some phylogenetic implications of purothionins.
The diploid species T. monococcum (A) synthetizes;
only the [l form, suggesting that the A genome of T.
diirttm is responsible for the genetic control oí [> formi
synthesis and thc B genome for that of the a fonn.
Analysis of the potential B genome donor, namely, the:
diploid species Aegilops speltaides (S — B), which doesi
synthetize the a form, substaritiates the hypothesis. This;
indicates that a and fi purothionins are the result of:
divergen! evolution at the diploid level and have come toi
coexist by thc convergcnt process of alloploid formal ion.
Diploid species
Alloploid species
Ñame
Ñame
Genome Phenolype
T. monococcum A
Ae. caudata
C
Ae. squarrosa D
Ae. speltoiúes S=B
Ae. ¡onguissima 5'.
Ae. bicornís
S"
^-~x\
Ancestral \
9 6
2 A¡T
s
^_^r
hi^uniarlstata
1Ae. comosa
H"]
Hj
\Ac. mteüulala C
\Ae. tnutica
M1
p, L
This points to hetcrogeneity within the x and ¡i purothionins, but further characterization of purothionins from
these species must wait. until enough material is grown.
In alloploid species where the parental genomes have
genetic information for electrophoret ically difieren!
purothionins, the coexistence of the a and fi forms is not
always observed. A similar observation can be madc
with the /?-sitoslerol ester systems. It seems that duplícate
genetic activity íor similar systeins represents an adaptive advantage but not nccessarily a physiological one.
Consequentiy redundant systems might. be lost in the
course of cvolution following alloploid íormation. It is to
be noted that all observed losses afíeet the additional
genomes and not the so-called pivotal genomes. This is
consistent with the cytogenetical observation that pivotal
genomes are completéis- homologous with knosvn diploids.
while the additional genomes are extensively modified
and only partially homologous with diploid analyzers.
Be sumen. En Triticnm durvm Desf. (genoniios AB), el
genomio A controla la síntesis de purotionina ¡i y el
genomio B la de purotionina a. Las especies diploides del
grupo Acgilops-Triiicitm sintetizan a ó fi, pero no las dos.
Genomes
Phenotype *
T. durum
AB
a,ÍU
T. aestivum
ABO
a,P,PL
Ae. cy/indrica
DC
a.PL
Ae. crassa
DMcr
a,PL
Ae. ventricosa Dhf
C }
-'•- Ae. juvena/is DC M a,PL
Ae. triuncialis 6 L l
a,PL
Ae. variabilis CUS'
Ae. triaristata CuM'r a,f3,PL
•- Ae. biuncia/is
ñ PI
rs \Ae. ovota
CUM°
Ae. columnaris C M
a,PL
* Purothionin a or p ; síerol esters PL (¡¡dimítate-lino/cale) or L (linoieaie)
C y t o g e n e t i c a l r e l a t i o n s h i p s in
Aef¡ilof>s-Trilinini
speeio* a n d d i s t v i h u t i o n of pnrotliioiiins a n d
/?-sito>lerol e s t e r s s y s t e i n s .
We liave íuiiher invcstigated the occurrenee oí a and /?
En numerosos aloploides de este grupo se observa la
forms in the reinaining species of the Acgilo ps-Tri ticit m
]
pérdida
de la' actividad sintética para la purotionina
group. A mkromet.ltod was used because only small <correspondiente a uno de los genomios.
amounts of material were available. The samplcs, 2()ü to
4()() mg of g round kernels were macerated for 2 h with
P. CAUHONIÍKÜ and V. GAKCÍA-OJ.MKDO
twice the aniotmt (v/w) oí petroleum ether (b.p. 35-G0°C).
The supernalant was transferred with the aid oí a capilInstituto Nacional de Investigaciones Agronómicas,
la ry tnl>e to a piece of paper (Whatman No. 3, 2 x S mm)
Madrid-3 {Spain), 2 June 1969
and evapora!ed in the process. Lipid was dissociated from
])iirothionin by treating the paper with 1 A' 11C1 in
ethanol: petroleum ether (3:1) with the aid of a capillarv
i1 A. K. I.ÍAI.I.S, \ V . S. M A L K a n d T . I I . H A K R I S , Cereal C h c i u . 19,
and then svas extracled by ¡inmersión in petroleum
27<J (1912).
ether íor 1 h. The dried pnj)er was wet with buffer and
-"- L. S. S T U A K T a n d T . 11. H A K I Í I S , C e r e a l C h e m . 19, 28S (1912).
a3 C. C. XI.MMO, M. 1". O ' S U I . I . I V A N ' a n d J . ]•'.. H I Í K N A U I M N , Cereal
the purolhionins fract ionnled by starch-gel electrophoresis.
Cliem. /.;, 28 (l'JGS).
Tile results are summarized in the Figure.The occurrence
4
Nr. l-'isiiEK, 1). G . K K H M A N anrl G . A . K. K I . T O N , Cereal Cliein. 7 5 ,
o! the previously deseribcd7 linoleaíe (L) and pahnilatc-IS (I«JOS).
linoleati- (l'L) systems íor />'-silosterol esters synthesis
5
IX G. K K D M A N a n d N . Kisnr.K, J . S e i . F d A^rie. 10, G51 (10hK).
has been also recorded.
*
<¡fi 1". (¡Aurí.\-üi.Mi:no, J. S n n - r o a n d K. G A K C Í A - I ' A I I U K . , A n . Inst.
In diploid species, all -1 possiblc combinations of
nao. Invt-st. a n i ó n . 17, 133 (19í">fi).
77
purothionin and slerol esters pheuots'pes are present.
I'. G A K C Í A - O I . M I Í I K ) , N a t n r e 220, l i l i (lOí.S).