Origin of 2N gametes in C. reticulata cv fortune mandarin

1•

81-22

ORIGIN OF 2N GAMETES INC.RETICUlATA CV FORTUNE MANDARIN

Cuenca

1., Navarro L., Ollitrault P.

Instituto Valenciano de Investigaciones Agrarias. Carretera Moncada-Naquera

Km.

4,546113

Moncada, Valencia, Spain

Citrus are most important fruit crop worldwide. Seed1essness is a key characteristic for

the fresh fruit market and the development of triploid hybrids is one strategy developed by

several groups over the world. Indeed, triploid hybrids are generally sterile and produce

seedless fruits and do not pollinate other varieties. Triploid citlllS hybrids can be obtained by

several strategies, including hybridization betwe6n diploid parents.

Mechanism of 2n gamete formation and its implication on parental heterozygosity restitution

is

a main parameter determining

the genetic

and phenotypic structure of the

triploid

population. In the case of Citrus it has been shown that the 2n gametes are of maternaI origin.

It

has been proposed that the origin of 2n gametes is from the second division restitution

(SDR) in Clementines and from the first division restitution (FDR) in sweet oranges. No data

is available for other genotypes and particularly 'Fortune', a mandarin hybrid producing very

high rate of triploids in 2x x 2x crosses and massively used to create triploid progenies. The

aim of this work was to analyse the mechanism of 2n gamete formation in 'Fortune' mandarin

genotype.

One hundred and five triploid hybrids from the crosses between 'Fortune' as female diploid

parent and 'Murcott' or 'Mandarino ComÛIl' as male diploid parents were genotyped for

twenty- four codominant molecular SSRs (Simple Sequence Repeat) markers using a capillary

genetic fragment analyzer. Estimation of ailelic doses from relative peaks area ailowed

inferring the female and male gamete structures and thus the heterozygosity restitution in the

2n gametes.; this demonstrated that ail triploid arise from 2n megaspores. The unimodal

distribution of heterozygosity restitution in the 2n megaspores among the analyzed genotypes

suggests that an these 2n gametes arise from a same mechanism. Restitution of maternaI

heterozygosity for the used rnarkers makes suppose that underlying mechanism in the 2n

gamete formation is SDR. Indeed there are six markers with less than 50% of maternaI

heterozygosity restitution, which is incompatible with FDR hypothesis. SDR hypothesis is

coherent with the results published in case of the clementine, which is one of the parents of

the

'Fortune'

variety.

Under

this

hypothesis,

the

relatively

high

global

heterozygosity

restitution level (60,95%) should indicate that a majority of the analyzed markers are far frorn

the

centromeres.

This

genetic

struc turation

will

soon

be

confronted

with

phenotypic

variability and compared with structuration obtained with other triploid creation strategies

such as 2x x 4x hybridization.

Keywords: citrus, mandarin, triploid, 2n gametes, meiosis

'.'

;'-;.,

r:.~r i-J~ .~~ Usboa2010 236

504.022

Tetraploid

Citrus limonia Rootstocks Are More

Tolerant to Water Deficit than Parental Diploids and

Present Large Gene Expression Changes in Roots

Morillon, R.u; Thierry, A.2; Brumos, P; Colmenero,

J.

M.3; Iglesias, D.3; Pina,

J.

A.4; Tadeo, F.3; Talon, M.3; Navarro, L.4; Ollitrault, P.s

ICENTRE DE COOPÉRATION iNTERNATIONALE EN RECHERCHE AGRONOMIQUE POUR LE DÉVELOPPEMENT(OMO),

UPR AMÉLIORATION GÉNÉTIQUE DES ESPÈCESÀMULTIPLICATION VÉGÉTATIVE, AVENUE AGROPOLIS -TAA-n/o!,

34398MONTPELLIERCEDEX ),FRANCE

: CENTRE DE COOPÉRATION INTERNATIONAlE EN RECHERCHE AGRONOMIQUE l'OUR LE DÉVELOPPEMENT (CIRAC).

MA.CENTRO DE GENOMICA, CTRA. MONC\DA-NAQUERAKM ),46113MONCADA, VALEN'IA, SPAIN,FRANCE

IINsnnrro VALENClANO DE INVESTIGACIONES AGRAR1AS; CENTRO DE GENOMICA. CTRA.~fONCADA-NAQUERA KM 5,-l61 1;MONCADA, VALENCiA, SPAIN

+(NSTITUTO VALENClANO DE INVESTIGACIONES AGRARlAS, CENTRO DE flROTECCION VEGETAL y BIOTECNOLOCIA, CTRA.MONCADA~NAQUERAKM ),46113MONCADA, VALENCIA, SPAIN

ICENTRE DE COOPÉRATIONINTER"'~ATIONALEEN RECHERCHE AGRONOMIQUE POUR LE DÉVELOPPEMENT, MA, ŒNTRO DE PROTECCION VEGETALyBIOnCNOLOGlA,CTRA.MONCADA~NAQUERAKM ), -+6IIJMONCAOA, VALENCIA., SPAIN,

FRANCE ,.

Warer shorrage is one of rhe'main abioric consrraiors affecring growrh and yield in cirrus. In this work, we investigated the wlerancewwarer mess of diploid and tetraploid seedlings of Rangpur lime (Citrus limonia) and also their behaviour as rootsrocks of Valencia Delta orange (Citrus sinemis) variery. The tetraploid (4x) !ine arose from chromosome doubling in nucellar cells of diploid(2x) Rangpur lime and has srricrly the same allelic composition chan che2x one. Ar the beginning of rhe suess, leaf sromatal conductances of 4x seedlings and Valencia Delta orange grafred on 4x rootswcks wete respectively lower rhan rhose of2x seedlings and Valencia Delta orange grafted on2x rootsrocks. At che end of che experimeor, 4x seedlings and Valencia Delta orange grafted on 4x showed the highest rolerances. This work suggests that greater tolerance is linked to a more efficieor regulation of gas exchanges in4x seedlings and varieties grown on 4x genorypes. Investigations of ABA root cooreor in2x and 4x suggest chat constitutive biosyorhesis of this hormone is higher in 4.'<'. To have a better understanding of the impact of2x and 4x roomocks on scion, we have also invesrigared gene expression using 20 K cDNA microarrays and qRT-PCR in Valencia Delta leaves grafted on2xand4.xroorsrocks in coorrol and warer deficit conditions. Expression of candidare genes involved in warer deficit tolerance was also monirored at me roOt level using qRT-PCR. In coorrol condition, those differeor genes, including NCED 1 which is involved in che last srep of ABA biosynchesis, wete all shown ro be up reguJared in 4.'<' roots when comparedw2x.

S04.023

Distinctive Transcriptome Response

of Two Strawberry (Fragaria xananassa)

Cultivars to

Colletotrichum acutatum Infection

Amil-Ruiz. F.l; Encinas-Villarejo, S.l; de los Santos, 8.2;

Munoz-Mérida, A.3; Mercado,

J.

A.4; Trelles, 0.3;

Pliego-Alfaro, F.4; Romero, F.2; Munoz-Blanco,J.1;Caballero,

J.

L

1

'UNIVERSJOAD DE COROOBA, DPTO. DE 810QuiMlCAy810LOCÎA MOLECULAR, CAMPUS DE RAB,".NAlES,sIN,EOIF. SEVERO OCHOA(c6),PLANTA BAjA-,\LA NORTE.[4071.CORDOBA, ANDALUdA.SPAIN

:L\S TORRES-TOMEjIL, I.F.A.P.A.-JUNTADE ANDAWciA,ALCAr.ADELRio.41200,SEVILLA, ANDALUciA. SPAIN 'UNIVERSIOAD DE MALAGA. DPTO. DE ARQUITECTURA DE COMPUTACION, CAMPUS DE TEATINOS.29°]1,,\'lÂ1.AGA• .\NDAWcl'\, SPAIN

~UNrvERSIOAD DE ....v.u.GA, orTO. DE BIOLOGl-\ VEGETAl. FACULTAD DE CIENeIAS. CAMPUS DE TEATlNOS,29°71.

MÂL\GA. ANDALUCiA. SPAIN

Strawberry (Fragaria xananassa) yields are srrongly affected by fungal diseases and pesrs (i.e. Colietotrichum spp., are major pachogens of mawberry), forcing the ex-cessive use of chemical products (mosrly environmeoral cooraminanrs) ro control rhem. Resisranr culrivars are a prioriry of most mawberry breeding programmes. However, !iule is known abour rhe generic basis rhar coorrol strawberry resisrance to parhogens, and rorally resistaor cultivars have not yet been reporred. A1rhough mo-lecular markers of disease resistance in strawberry have been reporred, che ocroploid genetic strucrure of commercial strawberry makes it difficult ro associare molecular markers wich disease resistance genes. To gain insighrs ioro rhe generic mechanisms

of defense against C acutatum,1 Camarosa and Andana) exhibitin analyz.ed. An in-house cDNA rr was fabricared from a srrawberry obtained in response ro rhis pat cultivars was performed before a was significandy alrered (Pvalue= (70 up-124 down-regulared), ane clusively alrerated in Camarosaa; up-reguJared in both cultivars. In known gene of che public databa funcrion. Over-expression andsi analysis of candidare genes. Valu< effective coorrol straregies to inm

504.024

Expression Profiles

0

in Responses to Aph

Ch~~_nthe_mum

Cul

He,

J.;

Chen, F.; Chen, S. COLLEGE OF HmrrICULTURE, NANJING AGRICULl

In order ro reveal how defense-relar

mum(Chrysanthemllm grandifioru

0.5 h, 1h, 3 h, 6 h, 12 h, 24 h, 3 expression profiles of genes involve and flavonoids pathway including phenylalanine ammonia lyase (PAl lare 5-hydroxylase (F5H), chalcone (DFR) were derermined using real· rivars differing in aphid resistance. COMT and F5H were induced in 1 resistam cultivar 'Han6' and suscej were induced only in rwo aphid re: 'Jinba' ar any time point. Thetran~

genes increased more rapidly and p( and 'Han6' than in the susceptiblt genes reached their orst peak at 1 h, resisram cultivar 'Keiun', and peakt sistant cultivar 'Han6'. While in su 6 h, 3 d, 6 h, 12 h, respectively. Th, to aphid inoculation were differen suggesring that rhese genes probabl chrysaorhemum.

504.025

C10ning of Genes Cor

and Salt Tolerance

by

CDNA Library in Vege

..

Zhu,Y.1; Yang, 1:.2; Gai,

J.1

'NATIONAL CENTER fOR SOYBEAN IMPROVEMEI UNrvERSITY. WEIGANG NO. 1. 210095, SANJING.Jil

:COLLEGE. OF HORTICULTURE. NANJING AGRICULTUI

ro obrain genes conferring allergeni( bean [Glycine max(L.) MerL], afuJ

seeds of the cultivar' N99-10'Wa! phoresis results showed rhat most of 2.0 kb, with an average size around 8 the recombination rate was above 991

library construcred was a full-lengch selection followed by sequencing of ch library, a toral of 642 expressed sequel