Isolation and characterization of an improved stra

Authors: ShaSha Chen HongChang Ding XingHong Yan

Publish Date: 2016/02/11

Volume: 28, Issue: 5, Pages: 3031-3041

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Abstract

The blades of the wildtype strain of Porphyra chauhanii PCWT were irradiated with 60Coγ rays and cultured at high temperature 30 °C for 25 days The surviving somatic cells of the irradiated blades were isolated enzymatically and were regenerated into whole blades and screened at high temperature Vigorously growing blades at high temperature were selected and individually proliferated A genetically homozygous and freeliving conchocelis strain of TR5 was obtained through parthenogenesis Subsequently TR5 was compared with PCWT for hightemperature resistance growth contents of major photosynthetic pigments and the releasing ability of monospores and conchospores The results showed that the survival percentage division and rhizoid germination of conchospores were not significantly different between TR5 and PCWT at 18 and 23 °C but the survival percentages were 2612 and 3293  higher the division percentages were 428 and 726  higher and the rhizoid germination percentages were 943 and 1995  higher in the former than in the latter at 27 and 29 °C respectively When F1 gametophytic blades of TR5 and PCWT were firstly cultured at 23 °C for 30 days and then cultured at 18 23 and 27 °C for another 10 days the absolute growth rates of TR5 blades were 44 43 and 104 times those of PCWT and the relative growth rates were 11 11 and 20 times those of PCWT respectively The apical and middle parts of PCWT blades were disintegrated due to the release of a large number of monospores after culturing for 15 days at 27 °C or 10 days at 29 °C and only the basal parts of the blades remained intact On the other hand TR5 blades grew rapidly with normal color and shape without releasing monospores and were slightly curled even after being cultured for an additional 30 days In addition the contents of three major photosynthetic pigments chlorophyll a Chl a phycoerythrin PE and phycocyanin PC and the conchospore numbers in TR5 at a suitable temperature 23 °C were 667 2442 1157 and 920  higher than those of PCWT respectively Meanwhile the blades of TR5 were 232  thinner than those of PCWT The results indicated that TR5 has thinner blade higher contents of the major photosynthetic pigments faster growth speed higher temperature resistance has larger number of conchospores released and no monospore release as compared with PCWT It therefore has potential to be developed into a new variety suitable for cultivation in the aquaculture areas with high temperature in the coast of South ChinaThe study was supported in part by the National High Technology Research Development Program of China “863” Program grant no 2012AA10A411 National Natural Science Foundation of China grant no 31072208 Ministry of Agriculture of China grant no 200903030 National Agricultural Science and Technology Achievements Transformation Project grant no 2013GB2C220537 Shanghai Committee Key Scientific Research Project grant no 10391901100 State Oceanic Administration of China grant no 201105008201105023 Shanghai Universities FirstClass Disciplines Project of Fisheries Science and Technology Commission of Fujian Province project no 2011NZ00011 and Special Fund of Fujian Provincial Governor project no 2014S147710

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