Rice Genetics IV - IRRI books - International Rice Research Institute

vealed that the efficiency of GUS staining was 2.0% (106 of 5,353) for leaves, 2.1%(113 of 5,353) for roots, 1.9% (133 of 7,026) for flowers, and 1.6% (31 of 1,948) forimmature seeds (Fig. 4). Among the 106 GUS-positive lines in leaves, 15 (14.2%)were leaf-specific. Likewise, 25 (22.1%) lines were root-specific among the 113 GUSpositivelines in roots. We also obtained data indicating that the efficiency of gusexpression in pGA1633 lines was 1.1% (8 of 750) for leaves and 0.9% (7 of 750) forroots. These values are lower than those of pGA2144, indicating that the modifiedOsTubA4 intron increased gus tagging efficiency.The staining patterns of the 106 lines that showed GUS activity in leaves wereobserved in detail (Table 1). The vein-preferential GUS staining pattern was the mostfrequently observed (43.4%) and 14 (13.2%) lines were stained preferentially in mesophyllcells between veins. In most samples, GUS staining was observed strongly inboundary regions exposed by cutting. A high concentration of cellulose, lignin, silicacells, and wax in rice leaves could have obstructed penetration of the GUS substrates.Table 2 summarizes the GUS staining patterns in roots. A majority of the lines showedLeaves 2.0%Roots2.1%Flowers 1.9%Seeds1.6%01 2 3(%)Fig. 4. The frequency of GUS expression in various organs oftransgenic plants. GUS activities were analyzed from leaves androots of 5,353 seedlings, mature flowers of 7,026 transgenic plants,and developing seeds of 1,948 plants.Table 1. GUS assay in leaves of transgenic rice plants a .GUS staining patternsGUS-positiveLines %Mesophyll 14 13.2Spots 14 13.2Veins 46 43.4Veins, mesophyll 28 26.4Veins, spots 2 1.9Mesophyll, spots 2 1.9Total 106 100a5,353 lines were tested.258 Gynheung An et al