[Solved]-using browserify-css in gulp-Reactjs

var appBundler = browserify({
    entries: ['./app.js'],
    transform: [
      ['babelify', {
          "presets": ['es2015', 'react']
        }
      ],
      ['browserify-css']
    ]
    });

  appBundler.bundle()
    .pipe(buffer())
    .pipe(gulp.dest('./dist'));