Introduction Zea mays 4 1977 1999 1996 1978 2004 1999 2004 2007 2007 + 1993 2007 1998 2002 2003 1990 1992 1994 1995 1998 2000 2000 1969 tie-dyed1 (tdy1) sucrose export defective1 (sxd1) 1996 2001 2006 1944 1985 1990 2007 tdy1 sxd1 sxd1 sxd1 1996 tdy1 sxd1 tdy1 2006 tdy1 tdy1 2007 Sxd1 sxd1 2003 1996 2000 2001 2004 2006 Tdy1 Sxd1 tdy1 sxd1 2 Tdy1 Sxd1 tdy1 Tdy1 Sxd1 Tdy1 Sxd1 Tdy1 Materials and methods Plant materials tdy1-Reference (tdy1-R) 2006 sxd1-1 1996 2 tdy1-R sxd1-1 1 Morphological analyses tdy1-R n sxd1-1 tdy1-R sxd1-1 Aniline blue staining Leaf strips 1 cm in width were cut from mutant and wild-type leaves. The abaxial epidermis and the mesophyll cells directly beneath it were gently scraped away with a single-edge razor to expose the inner leaf tissues. The leaf strip was placed on a slide, briefly stained with a 0.05% aniline blue and immediately viewed using a 360–370-nm excitation filter and a 420-nm long pass emission filter on a Nikon Eclipse 80i fluorescent microscope. Epifluorescent illumination was provided by a 100-W mercury lamp, and images were recorded using a DXM1200F Nikon digital camera. TEM analyses 1969 Chlorophyll quantification Relative levels of total chlorophylls were quantified from leaves using a SPAD 502 Data Logger Chlorophyll Meter (Spectrum Technologies). For each tissue, 30 samples were measured, and the experiment was performed three times. Representative data from one replicate are shown. Sugars and starch quantification 2001 1999 Tocopherol quantification 2003 Results tdy1-R sxd1-1 tdy1-R sxd1-1 1 sxd1-1 1 1 sxd1-1 tdy1-R 1 tdy1-R 2007 sxd1-1 tdy1-R 1 tdy1 sxd1 Tdy1 Sxd1 Fig. 1 tdy1-R sxd1-1 a dark green b  sxd1-1 c  tdy1-R d f d e  sxd1-1 f  tdy1-R Scale bars  tdy1-R sxd1-1 sxd1-1 1996 2000 2001 tdy1-R 2 sxd1-1 2 2000 tdy1-R 2 tdy1-R tdy1-R tdy1-R Fig. 2 a arrow b e black dotted line X P VP BS M b e b arrowhead c  sxd1-1 arrow d  tdy1-R e  tdy1-R sxd1-1 arrow sxd1-1 Scale bar a b e  tdy1-R 3 sxd1-1 3 1996 2000 2001 tdy1-R 3 tdy1-R 3 tdy1-R tdy1-R sxd1-1 Fig. 3 a-d Arrows a b  sxd1-1 c  tdy1-R d  tdy1-R sxd1-1 sxd1-1 (e g i) tdy1-R (f h j) e–j  e f  g, h i j BS M Scale bars  Double mutant plants show more severe growth defects than either single mutant tdy1-R sxd1-1 2 2 1 sxd1-1 2001 tdy1-R 2006 Tdy1 Sxd1 Table 1 2 Family # Total Wild type tdy1-R sxd1-1 tdy1-R sxd1-1 2 DB 5503 93 48 22 16 7 2.0 P DB 5512 95 52 23 15 5 2.1 P DB 5523 93 55 18 15 5 0.6 P Total 281 155 63 46 17 2.9 P 2 tdy1-R sxd1-1 2 tdy1-R sxd1-1 4 2 4 tdy1-R sxd1-1 tdy1-R sxd1-1 tdy1-R sxd1-1 tdy1-R sxd1-1 4 2 tdy1-R sxd1-1 4 sxd1-1 tdy1-R sxd1-1 2 tdy1-R sxd1-1 2 tdy1-R sxd1-1 4 1 sxd1-1 tdy1-R sxd1-1 tdy1-R 4 Fig. 4 2 tdy1-R sxd1-1 a c tdy1-R, sxd1-1 tdy1-R; sxd1-1 a b  tdy1-R sxd1-1 c tdy1-R sxd1-1 sxd1-1 tdy1-R d tdy1-R sxd1-1 Scale bars  Table 2 2 Phenotype Plant height wt% Tassel length wt%  Anthesis Ears (%) Wild type a 100 a 100 a 100 tdy1-R b 89.2 b 86.8 b 100 sxd1-1 c 76.6 c 71.2 b 81 tdy1-R sxd1-1 d 64.5 d 48.6 c 53 t sxd1-1 sxd1-1 2 sxd1-1 3 tdy1-R sxd1-1 Leaf tips of double mutant plants have the greatest reduction in chlorophyll levels tdy1-R sxd1-1 1 3 tdy1-R sxd1-1 sxd1-1 tdy1-R sxd1-1 sxd1-1 Tdy1 Sxd1 Table 3 2 Phenotype Chlorophyll Wild type a tdy1-R a sxd1-1 b tdy1-R sxd1-1 b tdy1-R c sxd1-1 c tdy1-R sxd1-1 d n t Sugar accumulation in double mutant leaves is greater than in either single mutant 1 Tdy1 Sxd1 2 5 tdy1-R 2006 sxd1-1 tdy1-R sxd1-1 tdy1-R sxd1-1 tdy1-R Tdy1 Sxd1 Fig. 5 tdy1-R sxd1-1 Abbreviations tdy1-R sxd1-1 Different letters t  Tdy1 Sxd1 Sxd1 sxd1 2003 Tdy1 Sxd1 tdy1-R 4 tdy1-R sxd1 2003 tdy1-R Tdy1 Sxd1 Table 4 Tocopherol quantification Phenotype Tocopherol Wild type a tdy1-R a tdy1-R a sxd1-1 nd nd t Discussion Tdy1 Sxd1 tdy1 sxd1 Tdy1 Sxd1 sxd1 tdy1-R Tdy1 Sxd1 sxd1 tdy1-R tdy1-R tdy1-R sxd1-1 Tdy1 Sxd1 tdy1 Chlorotic leaf tissues do not retain sink identity tdy1-R 2006 tdy1-R sxd1-1 Tdy1 tdy1 A model for TDY1 function 6 2004 2007 sxd1 6 1996 2000 2001 Fig. 6 M BS VP CC SE Green yellow White circles Magenta box blue boxes Arrows a b  sxd1-1 red box c  tdy1-R red X orange X  tdy1 2007 tdy1-R sxd1 1996 tdy1 6 tdy1 1994 1998 2000 2006 2007 tdy1 Tdy1 Tdy1 Tdy1 + + + 1994 1998 2000 2000 1998 2002 2003 tdy1-R tdy1-R sxd1-1 Tdy1 Sxd1 tdy1 Tdy1 Tdy1 Electronic supplementary material Below is the link to the electronic supplementary material.
 (DOC 31 kb)