Low gibberellin (GA) activity in tomato (Solanum lycopersicum) inhibits leaf expansion and reduces stomatal conductance. This leads to lower transpiration and improved water status under transient drought conditions. Tomato has three GIBBERELLIN-INSENSITIVE DWARF1 (GID1) GA receptors with overlapping activities and high redundancy. We tested whether mutation in a single GID1 reduces transpiration without affecting growth and productivity. CRISPR-Cas9 gid1 mutants were able to maintain higher leaf water content under water-deficit conditions. Moreover, while gid1a exhibited normal growth, it showed reduced whole-plant transpiration and better recovery from dehydration. Mutation in GID1a inhibited xylem vessel proliferation, which led to lower hydraulic conductance. In stronger GA mutants, we also found reduced xylem vessel expansion. These results suggest that low GA activity affects transpiration by multiple mechanisms: it reduces leaf area, promotes stomatal closure, and reduces xylem proliferation and expansion, and as a result, xylem hydraulic conductance. We further examined if gid1a performs better than the control M82 in the field. Under these conditions, the high redundancy of GID1s was lost and gid1a plants were semi-dwarf, but their productivity was not affected. Although gid1a did not perform better under drought conditions in the field, it exhibited a higher harvest index.

中文翻译：

---

番茄赤霉素受体中的突变抑制缺水条件下木质部的增殖并减少水分流失。

番茄（Solanum lycopersicum）中的低赤霉素（GA）活性抑制叶片膨胀并降低气孔导度。在短暂的干旱条件下，蒸腾作用降低，水质改善。番茄具有三个具有重叠活性和高冗余度的GIBBERELLIN-INSENSITIVE DWARF1（GID1）GA受体。我们测试了单个GID1中的突变是否在不影响生长和生产力的情况下减少了蒸腾作用。CRISPR-Cas9 gid1突变体能够在缺水条件下维持较高的叶片水分含量。此外，尽管gid1a表现出正常的生长，但它显示出减少的整个植物蒸腾作用和更好的脱水恢复能力。GID1a中的突变抑制木质部血管增殖，从而导致较低的水力传导。在更强的GA突变体中，我们还发现木质部血管扩张减少。这些结果表明，低GA活性会通过多种机制影响蒸腾作用：它会减少叶面积，促进气孔闭合并减少木质部的增殖和扩张，从而降低木质部的水力传导率。我们进一步检查了gid1a在现场是否比对照M82更好。在这些条件下，丢失了GID1的高冗余度，并且gid1a植物处于半矮状态，但是它们的生产力没有受到影响。尽管gid1a在田间干旱条件下表现不佳，但其收获指数更高。