百香果及相關種之Peroxidase及Glutamate Oxaloacetate Transaminase同功異構酶的變異性與遺傳分析

Inheritance and Genetic Variability of Peroxidase and Glutamate Oxaloacetate Transaminase Isozymes in Passion Fruit and Related Species

百香果及相關種10個屬種其PRX同功異構酶，各具有一特徵條帶伴生系列對影條帶，其為受單基因座所控制，命名之為Prx-2基因。種間Prx-2異型酶有8種交替型，以P. alata最快Rp0.58，P. incarnata最慢Rp 0.34，黃果種搜集的六個種源皆呈Rp0.42，列之為F型，紫果種皆為Rp0.35，列為S型。Prx-2等位基因表現共顯性及劑量效應，其量的表現度隨葉齡而提高，於成熟葉達最高活性並保持穩定性。百香果Prx-2基因之多態型，可有效利用為種間遺傳標誌，及雜交之指標。百香果種內種間GOT同功異構酶條帶多而密集成群，數目、相對活性及泳動性變異很大。黃、紫果種自交子代GOT條帶群皆表現與親本一致，種內或種間雜交代，則表現為兩親之累加性，並有共顯性、劑量效應及雜交雙體等之特性。F2族群可分離為兩親本之條帶群，及雜交累加型，其符合於單一基因座之遺傳行為，稱之為Got-X基因庫。GOT同功異構酶條帶群受Got-X基因座所控制，由七種以上之連鎖基因所組成，此基因小族儼如一遺傳單位。每一屬種至少具有四個活性基因，其餘為低活性或無效基因。種間Got-X之變異主要由於基因重複數目及活性之改變，連鎖基因小族有助於保持固定之異質結合性。紫、黃果種兩者之Prx-2及Got-X基因群皆呈同質結合，且互為不同交替型，兩者基因型呈相當歧異化。栽培種「臺農一號」分析為紫、黃果種之累加型，其Prx-2及Got-X基因型模式分別為S/F及bCDE-H-/-c-EGHI。

Zymograms of peroxidase (PRX) isozymes in 10 Passiflora species each display one unique dense PRX-2 band characterized by accompanying a series of shadow bands. Eight types of PRX-2 allozymes were distinguishable among species. Yellow passion fruit revealed as F type Rp 0.42 in all six accessions and S type Rp 0.35 was found in purple passion fruit, these altered allozymes were analyzed through progeny testing proved to be controlled by single locus assignated as Prx-2 gene. The Prx-2 alleles express codominance and pronounced allelic dosage effect. Quantitative expressivity of both F and S alleles increased as leaf development, and remained persistent through the maturation in either homozygote or heterozygote. The relative activity of F allele was a little higher than S allele. The polymorphic Prx-2 genes could be used as prominent genetic markers for species or hybrid identification. High variation in band number, relative intensity and mobility of GOT isozymes were observed in Passiflora species. The GOT band clusters of interspecies could be classified into I, II and intermediate groups. Selfing progeny of purple or yellow passion fruits showed monomorphic multiple bands identical to parent respectively. The phenotypic expression of interspecific or intraspecific hybrids was also respectively exhibited one uniform cluster likely derived from the additivity of both parental band clusters. The characters of codominance, dosage effect and one nonparental band were noticed. Two types of parental band cluster and one additively hybrid banding pattern were recovered in F2 population. Proposed genetic hypothesis is the multiple bands of GOT isozymes encoded by Got-X locus which is composed of more than 8 genes in group I species and additionally three genes specified the slower migrating in the group II. Each species possess 4-6 active genes and the others are low activity or null alleles. The compound linked genes inherited as one genetic unit. Linked duplication conducted to fixed heterozygosity.