|Park, Sunghun - TEXAS A&M UNIV|
|Kang, Tae-Suk - YONAM COLL AGRIC|
|Kim, Chang-Kil - SANJU NATL UNIV|
|Han, Jeung-Sul - NATL HORT RES INST|
|Kim, Sunggil - TEXAS A&M UNIV|
|Smith, Roberta - TEXAS A&M UNIV|
|Pike, Leonard - TEXAS A&M UNIV|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 13, 2005
Publication Date: July 13, 2005
Citation: Park, S., Kang, T.S., Kim, C.K., Han, J.S., Kim, S., Smith, R.H., Pike, L.M., Hirschi, K.D. 2005. Genetic manipulation for enhancing calcium content in potato tuber. Journal of Agricultural and Food Chemistry. 53(14):5598-5603. Interpretive Summary: Potatoes are the largest vegetable crop in the United States and are an important agricultural commodity worldwide; however, most potatoes contain little calcium, so potatoes serve as only minor components of total dietary calcium intake. Increasing nutritionally available calcium levels in potato tubers could enhance calcium dietary intake and lower the incidence of osteoporosis, a major health care issue. Here we have increased calcium levels in potatoes through genetic engineering. This is an important first step for making healthier potatoes.
Technical Abstract: Increased calcium (Ca) in potatoes may increase the production rate by enhancing tuber quality and storability. Additionally, increased Ca levels in important agricultural crops may help ameliorate the incidence of osteoporosis. However, the capacity to alter Ca levels in potato tubers through genetic manipulations has not been previously addressed. Here we demonstrate that potato tubers expressing the Arabidopsis H+/Ca2+ transporter sCAX1 (N-terminal autoinhibitory domain truncated version of CAtion eXchanger 1) contain up to 3-fold more Ca than wild-type tubers. The increased Ca appears to be distributed throughout the tuber. The sCAX1-expressing potatoes have normally undergone the tuber/plant/tuber cycle for three generations; the trait appeared stable through successive generations. The expression of sCAX1 does not appear to alter potato growth and development. Furthermore, increased Ca levels in sCAX1-expressing tubers do not appear to alter tuber morphology or yield. Given the preponderance of potato consumption worldwide, these transgenic plants may be a means of marginally increasing Ca intake levels in the population. To our knowledge, this study represents the first attempts to use biotechnology to increase the Ca content of potatoes.